This recipe blends two textures I adore: the dense, fudgy depth of a chocolate square and the gentle, chewy spring of mochi. I first tried this pairing on a rainy afternoon when I had a bag of mochiko sweet rice flour in the pantry and a craving for something intensely chocolatey but not cakey. The first bite surprised me; the exterior is set like a brownie while the interior gives a pleasant, elastic chew that keeps you coming back. It quickly became a favorite for potlucks and late-night treats in my house.

I remember bringing a pan to a small gathering and watching guests circle the plate, asking if the texture was intentional. Kids loved how it stuck slightly to their lips, and friends appreciated the depth from Dutch-processed cocoa and the pockets of chopped dark chocolate on top. These squares travel well and hold their flavor for a couple of days at room temperature, making them a go-to when I need a make-ahead dessert with an Asian-inspired twist.

Ingredients

• Mochiko sweet rice flour: Use 1 cup (about 8 ounces) of mochiko. This glutinous rice flour is what gives the interior its characteristic chew. I like Koda Farms mochiko because it’s finely milled and consistent.
• Unsweetened cocoa powder: 1/2 cup. I prefer Dutch-processed for a mellow, dark chocolate flavor, but natural cocoa works too for a brighter cocoa note.
• Granulated sugar: 1 cup. Provides structure and sweetness. For a deeper flavor, you can use half brown sugar or substitute a little maple syrup, but that will change the set.
• Baking powder: 1 1/2 teaspoons. A small lift helps the crumb set without becoming cakey.
• Unsalted butter: 5 tablespoons, melted. Butter gives richness and helps the top set with a faint crisp edge.
• Large eggs: 2. Eggs add structure and richness; beat them just until combined with the wet ingredients.
• Whole milk: 12 ounces (about 1 1/2 cups). This yields the right batter viscosity and adds creaminess. You can swap with full-fat plant milk for dairy-free options.
• Vanilla extract: 1 teaspoon. A small amount brightens the chocolate and balances sweetness.
• Chopped dark chocolate: 3 tablespoons, scattered on top for pockets of melting richness and a glossy finish when baked.

Instructions

Prepare and preheat:Preheat the oven to 350 degrees Fahrenheit and line an 8-by-8-inch baking pan with parchment paper, leaving a bit of overhang for easy removal. Proper lining ensures clean slices and prevents sticking.Combine dry ingredients:In a medium bowl whisk together 1 cup mochiko, 1/2 cup unsweetened cocoa powder, 1 cup granulated sugar, and 1 1/2 teaspoons baking powder until uniform. Sifting is optional but helps remove clumps from powdered cocoa.Whisk wet ingredients:In a larger bowl, whisk 5 tablespoons melted butter with 2 large eggs until smooth. Add 12 ounces whole milk and 1 teaspoon vanilla extract, whisking until no streaks of egg remain. Room-temperature eggs prevent curdling and ensure even mixing.Mix batter:Pour the dry mixture into the wet ingredients and fold with a rubber spatula until evenly combined. The batter will be thicker than a typical cake batter but pourable. Avoid overmixing; stop when no dry pockets remain.Transfer and top:Pour batter into the prepared pan, smoothing the surface gently. Sprinkle 3 tablespoons chopped dark chocolate evenly over the top so you get molten pockets and a shiny finish as it bakes.Bake until set:Bake at 350 F for 60 to 70 minutes. Rotate the pan halfway if your oven has hot spots. The center should appear set and slightly springy; a toothpick will come out mostly clean with a few moist crumbs. Avoid underbaking, because hot mochi is very sticky and difficult to slice.Cool completely and slice:Allow the pan to cool on a wire rack to room temperature, at least 2 hours, or refrigerate to speed cooling. Use the parchment overhang to lift the slab out and slice into 12 pieces with a sharp knife, wiping the blade between cuts for clean edges.

Storage Tips

Store cooled pieces in a single layer in an airtight container at room temperature for up to 3 days. If stacking, separate layers with parchment paper to prevent sticking. To keep longer, wrap pieces tightly in plastic wrap and freeze in a sealed freezer bag for up to 3 months. Thaw at room temperature or warm gently in the microwave for 10 to 15 seconds to soften the center without making it too sticky.

Ingredient Substitutions

For dairy-free: replace melted butter with melted coconut oil and swap whole milk for full-fat coconut milk or an unsweetened almond milk; expect a slight coconut undertone. For lower sweetness: reduce sugar by 1/4 cup, but this will change texture and crumb slightly. If you prefer extra chocolate, fold 1/3 cup chocolate chips into the batter or scatter more chopped chocolate on top. Using natural cocoa instead of Dutch-processed will create a more acidic, brighter chocolate note.

Serving Suggestions

Serve slightly chilled or at room temperature. Garnish with a light dusting of powdered sugar or a sprinkle of flaky sea salt to accentuate the chocolate. These pair beautifully with green tea, strong black coffee, or a scoop of vanilla ice cream for contrast. For a party, cut into bite-sized squares and display on a platter with contrasting textures such as toasted sesame brittle.

Cultural Background

This hybrid draws on Japanese sweet rice flour tradition where mochiko is used to make chewy confections. Combining it with Western-style chocolate squares creates a fusion dessert that celebrates both textures: the glutinous chew of mochi and the rich chocolate profile of a classic brownie. Variations of rice-flour-based sweets are common across East Asia, and blending those textures with familiar flavors is a modern take that many family cooks have embraced.

Seasonal Adaptations

In winter, fold in 1/2 teaspoon ground cinnamon and top with chopped toasted pecans for warmth. In summer, swirl a fruit jam into the batter before baking and finish with fresh berries. During festive seasons, decorate slices with edible gold leaf or a dusting of matcha powder for a visual lift and complementary bitterness.

Meal Prep Tips

Make the slab ahead and refrigerate overnight for easier slicing in cleaner squares. Portion into single servings for lunchbox treats; they hold up well and don’t get soggy. If you plan to serve at a gathering, bake the day before and allow to come to room temperature; this lets the flavors harmonize and makes transport simpler.

These squares are a small, satisfying dessert that celebrates texture and chocolate in equal measure. They are forgiving enough for beginners and flexible enough for experienced cooks to experiment with flavors and toppings. Give them a try and make them your own.