Chocolate mochi mini cupcakes

Spray a 12-cup mini cupcake pan with vegetable oil or rub with butter, then dust lightly with granulated sugar. Preheat oven to 350F.
Combine melted butter and sugar, whisk until pale and completely incorporated. Add the lightly beaten egg and mix again until completely incorporated. In a separate bowl, whisk together the cocoa powder, mochiko, baking powder, making sure no lumps remain. Add this dry mixture to the butter/sugar/egg mixture and mix lightly with a spatula until there are no visible pockets of dry mix. Pour the coconut milk and vanilla over the top and fold into the batter until the batter isn’t lumpy. Divide evenly amongst the cupcake tins. Bake for 18 minutes, or until a toothpick inserted in the center comes out clean. Let the brownies rest 5 minutes in the tin before turning them out onto a rack to cool completely before eating.