For our December 2025 JOC Cooking Challenge, we’ll be baking rich, beautifully green Matcha Brownies that are perfect for the holiday season!

Nine square pieces of green matcha brownies with a shiny, slightly cracked surface are arranged on parchment paper. A teapot, tea cup, utensils, and a bowl of matcha powder are nearby.

This Month’s Recipe Challenge

The holiday baking season has officially begun, and I’m kicking off our year-end cooking challenge with these festive-looking recipe: Matcha Brownies!

These brownies are perfectly fudgy with a lovely balance of nutty sweetness and heavenly matcha flavor. Easy to make, delightfully Japanese, and perfect for tea time or as a homemade gift—I hope you’ll join in the fun!

Alternative Entry: If you don’t have good-quality matcha on hand, feel free to make the chocolate brownie version included in the recipe post.

Three thick, green matcha brownies are stacked on a white plate, with more brownies and a cup of tea in the background. The brownies have a rich, moist texture and a marbled surface.

The Prizes!

This contest is open to everyone worldwide, and we will randomly select 3 winners at the end of the challenge. Each winner will receive a $100 Amazon gift card.

Everyone who completes the JOC Cooking Challenge submission is automatically entered into the prize draw.

Please note that winners are not chosen based on how the creations look, but your submission must follow the recipe and meet the challenge requirements.

Before You Start

  • Be sure to read through the full recipe post first before baking.
  • If you have recipe-specific questions, please leave them in the comments on the recipe post. For any challenge-related questions, leave your comment below. We’re here to help!
A square baking pan lined with parchment paper contains a baked sheet of shiny, green matcha brownies. Surrounding the pan are bowls of matcha powder and white beans, and a wooden utensil.

How to Join the JOC Cooking Challenge

Make Matcha Brownies and follow the recipe as closely as possible so your final dish looks similar to mine.

To enter for a chance to win, simply complete these two steps:

  1. Email us your picture. Send one photo of your final dish to contest@justonecookbook.com by 12 pm (Pacific Time) on December 31, 2025, and;
  2. Leave a star rating and comment on the Matcha Brownies recipe post using the same email address you used for your photo submission.
  • Each person may submit only one entry.
  • Feel free to share your picture on social media and tag us @justonecookbook.

The Prize Winners

  • Liina
  • Yumi
  • Matijas

Congratulations! We contacted the winners via email.

Readers’ Photo Submissions (112 Entries)

A collage of sixteen images showing different matcha brownies, each baked in various pans and plates, with diverse textures, shapes, and shades of green and brown. Some are sliced, and some are whole or plated.
A collage of 16 photos showing different matcha brownies, each baked in various shapes, pans, and presentations, some sliced, some whole, and some served with fruit or held in hand.
A collage of sixteen images shows various green cakes, mostly rectangular or square, some sliced or plated, with different textures and presentations on trays, plates, or in baking paper.
A collage of various greenish-brown matcha brownies, shown whole, cut into squares, or arranged on plates and trays, highlighting different textures and presentations.
A collage of sixteen images showing various green matcha brownies and cakes, cut into squares or rectangles, displayed on plates, trays, and in containers, with different textures and backgrounds.
A collage of sixteen photos showing various matcha brownies, cut into squares or rectangles, displayed on plates, trays, or baking parchment, highlighting their green color and moist texture.
A collage of sixteen photos shows green brownies in various stages: whole in baking pans, sliced into squares, and served on plates, some garnished with herbs or a raspberry.

Past Cooking Challenges & Recipes

This is a quarterly online event on Just One Cookbook. We host the challenge in March, June, September, and December. We’d love for you to join us in each challenge! To receive the updates, be sure to subscribe to our weekly newsletter.