A tray lined with printed paper holds several neatly cut squares of golden brown curry fudge. A can of curry powder sits blurred in the background.

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Japanese Curry Roux is the secret behind the cozy chicken curry rice many of us grew up eating in Japan. With this simple homemade recipe, you can make the blocks ahead of time, skip additives, and adjust the spice level to your liking. It’s your shortcut to rich, flavorful curry whenever you need a quick, satisfying meal.

If you’re looking for more ways to use curry roux, try my Japanese Chicken Curry, Curry Udon, and Japanese Beef Curry next!

A tray lined with printed parchment holds several pieces of brown, square-shaped fudge stacked neatly. The fudge has a smooth top layer and a slightly crumbly texture underneath.

What is Japanese Curry Roux?

First sold in block form in 1956, Japanese Curry Roux (カレールー) is a blend of browned butter, flour, and warm spices pressed into a firm slab, which dissolves into broth and transforms it into curry sauce. Brands like S&B Golden Curry and Vermont Curry turned weeknight curry rice into a beloved household meal.

Namiko Hirasawa Chen

Why I Love This Recipe

  • Made with all-natural ingredients – No chemical seasonings, preservatives, or artificial flavors.
  • Easy to customize for your preferred taste and spice level, plus it’s unsalted.
  • Beginner-friendly! This is one of the simplest DIY recipes, and I was surprised by how easy it was the first time I made it.
Several pieces of square-shaped brown fudge are stacked on a tray lined with parchment paper printed with text. More fudge and a red canister are visible in the background.
A pot of Japanese curry is simmering with chunks of potatoes, carrots, onions, and meat. A ladle with curry roux blocks—perfect for those learning how to make Japanese curry roux—and a pair of chopsticks are held over the bubbling broth.

Ingredients for Japanese Curry Roux

Find the printable recipe with measurements below.

Jump to Recipe

Substitutions

  • Unsalted butter: I like to add salt later when cooking my curry sauce, so I use unsalted butter for the roux. If you use salted butter, reduce the amount of salt you add to the curry.
  • S&B Japanese curry powder: This mild, slightly sweet curry powder is my favorite brand. You can find it on Amazon or at Japanese markets. If you can’t get it, try my homemade Japanese Curry Powder recipe. Other curry powders work too, but they won’t give the same authentic Japanese flavor.
  • Garam masala: A warming Indian spice mix with cardamom, cloves, cumin, coriander, turmeric, nutmeg, and black pepper. If you don’t have it, you can use the individual spices or add more curry powder instead.
A tray lined with printed paper holds several square pieces of curry fudge. A glass dish with more fudge and a can of S&B curry powder are visible in the background.
A black staub containing Japanese beef curry.

How to Make Japanese Curry Roux

Cook

  1. Build the base. Melt butter in a saucepan over medium heat and stir in flour with a wooden spoon to combine. 
A wooden spatula stirs melted butter in a stainless steel pan on a stovetop. The butter is yellow and bubbling, indicating it is being heated or clarified.
A hand pours flour from a glass container into a pan of melted butter on a stovetop, mixing with a wooden spatula.
  1. Mix and cook it for 20–25 minutes until golden brown (see the next step to see the golden brown color).
A stainless steel whisk stirring a thick, creamy sauce in a metal saucepan on a stovetop, with light bubbles forming on the surface.
A stainless steel saucepan filled with a smooth, light brown sauce being whisked, sitting on a stovetop.
  1. Add the spices, then whisk and cook for 30 seconds.
A hand pours ground curry powder from a small bowl into a saucepan with a brown sauce, next to a metal whisk.
A metal whisk stirs a thick, brown curry roux in a stainless steel saucepan on a stovetop.

Assemble

  1. Mold the mixture in an airtight glass or metal container lined with parchment paper. Cool, then refrigerate overnight to solidify. 
A thick brown mixture is being poured from a pan into a parchment-lined rectangular glass baking dish on a light wooden surface.
A glass dish lined with parchment paper is filled with a smooth, glossy, brown sauce or mixture, likely being prepared for baking or setting. The dish rests on a light wooden surface.
  1. Cut the firm roux into cubes the next day and store in a glass container until ready to use.
A hand slices a block of brown matcha caramel fudge into squares on a cutting board lined with parchment paper.
Four rectangular blocks of golden-brown Japanese curry roux are arranged in a glass container with a green lid placed beside it on a wooden surface.

Nami’s Recipe Tips

  • Cook out the raw flour taste. Don’t cut the browning time short! Cooking the roux for a full 20–25 minutes ensures you cook out any raw flour flavor, developing a deep, nutty complexity for your curry sauce.
  • Stir constantly. Roux can scorch in seconds. Use a wooden spoon to start and switch to a whisk if the butter starts to separate.
  • Add cayenne sparingly. The heat will intensify as the cubes dissolve and simmer, so start with less and adjust to taste.
  • Season at the end. This roux is salt-free. When you cook your Japanese curry, taste the sauce after you mix in the roux and add salt (about 2–4 teaspoons per full block) to taste.

Variations and Customizations

  • Dairy-free: Swap in vegan butter.
  • Gluten-free: Use a cup-for-cup gluten-free flour blend.
  • Extra depth: Sauté minced garlic, ginger, or onion before adding the flour.
  • Thicker sauce: Increase butter and flour in equal amounts for a heartier cube.
Several pieces of square-shaped brown fudge are stacked on a tray lined with parchment paper printed with text. More fudge and a red canister are visible in the background.
Adding the curry roux.

How to Use Japanese Curry Roux in Your Recipe

  • How much to use: I find that 6–7 cubes per 4 cups (1 liter) of broth/water is about right. This is equivalent to one box of store-bought curry roux that calls for the same amount of liquid.
  • Add to your curry pot: Dissolve the roux, 1 or 2 cubes at a time, in a ladleful of hot broth before releasing it to the pot. If the homemade roux hasn’t solidified yet, you can add it directly to the broth.
  • Thicken: Simmer over low heat for 5–10 minutes. If it doesn’t thicken, add more roux. It’s possible that the veggies in your recipe released extra moisture, so please adjust based on the ingredients you’re cooking.
  • Adjust the seasoning: Taste the curry after the roux is fully dissolved and incorporated, preferably after 3–5 minutes of simmering. Add the salt or spice to your liking. This homemade roux recipe does not contain any salt.

What to Make with Japanese Curry Roux

With the homemade curry roux, you can cook a myriad of Japanese curry recipes anytime:

A white bowl containing sapporo soup curry.
A white oval bowl containing Katsu Curry garnished with Fukujinzuke.
A plate containing Japanese seafood curry made with pressure cooker.
A white bowl containing cold curry udon with sliced pork, boiled egg, and fresh vegetables.

Storage Tips

To store: Keep cubes in the fridge for up to 1 month or freeze for 3–4 months.

Frequently Asked Questions

Why is my Japanese curry sauce watery?

Too little roux, excess liquid, or watery vegetables can keep it runny. Typical veggies include carrots, potatoes, and onions. Stir in another cube and simmer until the sauce coats the back of a spoon 

How many roux cubes match a box of curry?

Six to seven homemade cubes equal one store-bought box designed for 4 cups (1 liter) of broth.

How to Make Japanese Curry Roux

4.68 from 810 votes
by Namiko Hirasawa Chen
A white enamel tray lined with printed paper holds several pieces of golden brown fudge. A jar labeled Oriental Curry Powder and a glass container of more fudge are in the background.
Learn how to make homemade Japanese curry roux from scratch with just five ingredients. This easy 30-minute recipe lets you adjust the flavor and spice to your taste. Freeze in cubes for rich, flavorful Japanese curry anytime!
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Equipment

Prep: 5 minutes
Cook: 30 minutes
Total: 35 minutes

Ingredients 
 

Servings: 1 block (8 cubes per block; 7 oz, 200 g; enough for 4 cups liquid)
  • 3.5 oz unsalted butter (7 Tbsp)
  • 3.5 oz all-purpose flour (plain flour) (about ¾ cup; use GF flour or rice flour for gluten-free)
  • 4 Tbsp Japanese curry powder (I recommend S&B Curry Powder; available on Amazon or make from scratch with my recipe here)
  • 1 Tbsp garam masala (see Notes)
  • ½ tsp cayenne pepper (optional)

Instructions

Before You Start

  • Gather all the ingredients. I highly encourage you to weigh your flour and butter using a kitchen scale. For weights, click the Metric button above. If you don't have a scale, here's how to measure flour with a measuring cup: Fluff the flour with a spoon, sprinkle it into the measuring cup, and level it off. Otherwise, you may scoop more than you need.
    A metal tray with butter, a glass bowl of flour, and three small bowls containing brown spices are arranged on a light wooden surface.

To Make a Brown Roux

  • In a small saucepan, melt 3.5 oz unsalted butter over medium-low heat.
    Nami's Tip: Cube the butter to melt it faster.
    Side-by-side images: on the left, a block of butter in a stainless steel pan; on the right, the butter is melting and being stirred with a wooden spatula.
  • Add 3.5 oz all-purpose flour (plain flour). Stir constantly with a blunt-end wooden spatula.
    What to Expect: The flour will absorb the water in the butter at this stage. If the mixture clumps into a thick, paste-like dough ball at first. Don't worry. As you keep stirring, the mixture will quickly smooth out into a fluid roux.
    A person adds flour to melted butter in a saucepan on the stove, then stirs the mixture with a wooden spatula to form a roux.
  • Keep stirring constantly over medium-low heat. As the moisture evaporates, the mixture swells, then fuses into a smooth, fluid roux.
    Nami's Tip: If the roux begins to separate, switch to a whisk and mix vigorously to recombine.
    Two images side by side: On the left, a hand stirs a thick yellow roux in a pot with a wooden spatula; on the right, a whisk mixes the smoother roux in the same pot as it cooks on the stove.
  • Keep stirring constantly for 20–25 minutes as the roux gradually deepens into a warm, golden-brown color. Watch closely near the end as it browns quickly. See the "brown roux" color in the next step.
    Nami's Tip: If your stove runs hot or if the mixture sputters or browns too quickly before the 15 minute mark, reduce the heat to low to avoid burning. Never raise the heat above medium-low to rush the process. Cooking out the raw flour taste creates a warm, toasty flavor that gives your curry rich depth.
    Side-by-side images of a metal pot on a stove with a whisk mixing a light-colored roux on the left and a darker golden-brown roux on the right, showing the progression of cooking.

To Make the Curry Roux

  • Add 4 Tbsp Japanese curry powder, 1 Tbsp garam masala, and ½ tsp cayenne pepper (optional) to the roux.
    A hand adds ground spices to a saucepan with a whisk and thick sauce on a stovetop, shown in two side-by-side images with slightly different spices being poured in.
  • Cook and stir for 30 seconds, then remove from the heat. The roux is now ready to use immediately or mold it into a block for later.
    Two side-by-side photos show a metal whisk mixing curry powder into a roux in a stainless steel saucepan on a stove, with the mixture becoming smoother and darker from left to right.

To Mold into a Block (overnight)

  • Transfer the roux to a 12.5 oz (1.5 cup) airtight glass container lined with parchment paper. Let it cool completely on the kitchen counter, then refrigerate to solidify overnight.
    Nami's Tip: Use a glass or metal container so the curry doesn't stain the container. I use a rectangle container to create 8 equal size cubes.
    Side-by-side photos: On the left, a thick brown mixture is being poured into a parchment-lined glass dish. On the right, the mixture sits smoothly spread in the dish, ready to set.

To Store

  • The next day, take out the curry block from the container. If the curry block gets stuck to the container, release it with a butter knife or an offset spatula.
    Two images show hands working with a glass dish lined with parchment paper. In the first, a pastry brush spreads liquid on top. In the second, the parchment and contents are being lifted from the dish.
  • With a sharp knife, cut the block into 8 cubes, about 1 x 1 inch (2.5 x 2.5 cm) each. Transfer the curry roux to a new glass container. Store in the refrigerator for 1 month or in the freezer for 3–4 months. Use them soon for the best flavor and aroma.
    A hand slices golden-brown squares on parchment paper, while the second image shows six squares neatly arranged in a glass container with a green lid nearby.

To Use in a Curry Recipe

  • Dissolve the roux gradually: Add 1 to 2 cubes at a time into a ladleful of hot broth to dissolve them completely before stirring them into the main pot. Recommend using 6–7 cubes (equivalent to one store-bought box) for 4 cups / 1L liquid. Allow the curry to simmer uncovered on low heat for 5–10 minutes after adding the roux.
    Nami's Tip: If it’s too thick, simply splash in a little extra water or broth. If it’s too thin, simmer it a bit longer to reduce, or stir in one additional cube.
    Two side-by-side images show a pot of Japanese chicken curry. The left image features chunky vegetables and tender chicken simmering in broth, while the right image shows the same pot after curry roux is added, transforming the soup into a thicker, rich brown curry.
  • Season to taste: Because this homemade roux is unsalted, taste the sauce once the cubes are fully dissolved and add about 2–4 tsp salt (per full block) near the end of cooking. Adjust extra curry powder or cayenne to reach your preferred spice level.
    Two images of a pot with Japanese chicken curry containing carrots, potatoes, and onions. In the first image, a hand adds seasoning; in the second, the curry simmers with visible vegetables.
  • Try it with my Chicken Curry, Instant Pot Curry, Vegetarian Curry, Beef Curry, Keema Curry, and Curry Udon!

Notes

Garam masala: If you can‘t find garam masala, you can add more curry powder or individual garam masala spices in its place. Different garam masala blends can vary significantly in intensity and flavor profile, so adjust the amount to taste.

Nutrition

Serving: 1block (8 cubes), Calories: 1175kcal, Carbohydrates: 92g, Protein: 15g, Fat: 86g, Saturated Fat: 52g, Polyunsaturated Fat: 4g, Monounsaturated Fat: 22g, Trans Fat: 3g, Cholesterol: 213mg, Sodium: 26mg, Potassium: 520mg, Fiber: 13g, Sugar: 1g, Vitamin A: 3132IU, Vitamin C: 4mg, Calcium: 155mg, Iron: 12mg

The nutrition facts shown are generated by an online calculator and are estimates only. Please consult a professional nutritionist for specific dietary needs.

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Editor’s Note: This post was originally published on March 18, 2013. A video and new images were added in August 2018. The recipe was revised and updated with fresh images and content on October 20, 2021. It was republished again with more helpful content on August 28, 2025.