Mochi brownies, or molten chocolate rice cake, is a fusion dessert that beautifully combine the chewy texture of traditional Japanese mochi, the fudgy richness of classic chocolate brownies, and the soft velvety center of a decadent lava cake.
In another bowl, combine all the wet ingredients (egg, melted butter, and milk).
Pour the wet ingredients into the dry ingredients, mix until well combined.
Pour half of the batter into the prepared cake pan. Add a layer of chocolate discs. Pour the rest half of the batter over the chocolate discs. Smooth the top with a spatula.
Bake in the preheated oven at 355℉/180℃ for 45 minutes.
Remove the cake pan from the oven. Gently lift the parchment paper to remove the mochi brownie from the pan and transfer it onto a cutting board. Cut the mochi brownie into 6 pieces.
If desired, place a chocolate bar on top of the sliced brownies and return them to the oven to bake at 220°F/105℃ for 2 minutes to create a molten chocolate topping.