Prepare the ingredients: Chop the chocolate into small pieces. Line the bottom of your 18x18 cm baking pan with parchment paper to make it easier to remove the brownies after baking.
Melt the butter and chocolate: Place the butter and chocolate into a heatproof bowl. Melt them together using the double boiler method (place the bowl over a pot of simmering water). Stir until the butter and chocolate are completely melted and combined. Alternatively, you can melt them in the microwave, checking and stirring every 10-15 seconds to prevent burning.
Mix the dry ingredients: In another bowl, sift the glutinous rice flour, cocoa powder, baking powder, and a pinch of salt together. Mix well to ensure the dry ingredients are evenly distributed.
