01 -
Preheat oven to 350°F. Pour melted butter evenly into a 9x9-inch baking dish and set aside.
02 -
In a large bowl, whisk together flour, light brown sugar, baking powder, salt, 1/2 cup granulated sugar, and 1/4 cup cocoa powder until thoroughly combined.
03 -
Whisk in whole milk and vanilla extract to the dry mixture until smooth and uniform.
04 -
Fold semi-sweet chocolate chips into the batter until evenly distributed.
05 -
Pour batter over melted butter in the baking dish and gently spread to the edges without mixing the batter into the butter underneath.
06 -
In a small bowl, whisk together the remaining 1/4 cup granulated sugar and 1/4 cup cocoa powder until combined. Sprinkle this mixture evenly over the batter.
07 -
Carefully pour hot water evenly over the entire top layer without stirring. Place the dish on a drip pan and bake uncovered for 40 to 50 minutes, until the top forms a firm crust.
08 -
Allow to cool for 10 minutes before serving. Optionally accompany with ice cream, whipped cream, or fresh fruit.