• It‘s very important to degrit the clams as soon as you purchase them. Follow my instructions (it‘s easy!) on how to degrit clams.
  
• Before You Start…Please note that this recipe requires 50 minutes of kombu soaking time (30 min) and pressurizing time (20 min). 

  Gather all the ingredients.
  

To Prepare the Kombu Stock (1 hour to overnight before cooking)

• To 3 cups water, add 1 piece kombu (dried kelp). Set aside to steep for at least 30 minutes to overnight. Then, remove the kelp before using this kombu dashi.
  

To Prepare the Ingredients

• Cut 3 onions in half and then cut the halves into 5 wedges. Cut 6 mushrooms into ¼-inch (5-mm) slices.
  
• Mince 2 cloves garlic and grate 1 knob ginger (keep the juice, too).
  
• Peel 6 oz medium shrimp and devein the back of shrimp with a skewer (the vein runs right along the back so you can insert the skewer and pull out the vein). For step-by-step photos, see my tutorial on how to devein shrimp.
  

To Cook the Seafood Curry

• Press the Sauté button on your Instant Pot (I use a 6 QT Instant Pot) and heat 1 Tbsp neutral oil.
  
• When the pot is hot, add the onion and coat with the oil. Then, add the minced garlic and grated ginger with juice and quickly mix well.
  
• Add all the seafood (12 manila clams, the shrimp, 6 oz calamari, and 6 oz bay scallops). Add ¼ cup white wine to deglaze the bottom of the pot with a wooden spoon. Scrape off the brown bits (called fond) stuck to the bottom of the pot, where all the flavors are.
  
• When the alcohol has evaporated, add the kombu dashi (the stock you made earlier) and add the mushrooms.
  
• Add 1 package Japanese curry roux (or homemade curry roux) and ⅛ tsp freshly ground black pepper. Use a spatula to push down the ingredients but keep the curry roux blocks on top so they won’t get stuck and burn at the bottom.
  
• Cover and lock the lid. Make sure the steam release handle points at Sealing and not Venting. Press the Keep Warm/Cancel button on the Instant Pot to stop the Sauté mode. Press the Pressure button to switch to the manual pressure cooking mode. Select Low pressure and press the Minus (-) button to change the cooking time to 5 minutes.
  
• For a stovetop pressure cooker: Cook on high heat until high pressure is reached. Then, reduce the heat to low but maintain low pressure for about 5 minutes.
• When it is finished cooking, the Instant Pot will switch automatically to the Keep Warm mode. IMMEDIATELY QUICK RELEASE the pressure/steam by sliding the steam release handle to the Venting position until the float valve drops down.

  Important: We don’t want to naturally release seafood curry because the seafood could overcook with the remaining heat.
• Unlock the lid and add 1 Tbsp soy sauce and grate ¼ apple into the pot. Mix well and make sure all the curry roux has been dissolved.
  
• Divide the 4 servings cooked Japanese short-grain rice on individual plates and serve the curry either to the side or on top.
  

To Store

• You can keep the leftovers in an airtight container and store in the refrigerator for up to 3 days.

To Reheat

• Leftover curry sauce will thicken into a paste as it cools, so it tends to burn while reheating. To avoid this, stir ½ cup (120 ml) water or more into the leftover sauce until loosened. Then, gently reheat it on low heat. If the sauce seems thin, continue heating with the lid off to reduce the sauce.