Preheat oven to 350°F (175°C). Grease and line an 8x8-inch baking pan with parchment paper.

Mix dry ingredients in a bowl: flour, cocoa powder, baking powder, and salt.

Whisk wet ingredients in a separate bowl: sugar, melted butter, eggs, vanilla, and milk.

Combine the dry ingredients with the wet ingredients. Stir until just combined—don’t overmix.

Pour batter into the prepared pan and spread evenly.

Bake for 20–25 minutes, or until a toothpick inserted in the center comes out with moist crumbs.

Cool in pan for 10 minutes, then transfer to a wire rack. Let cool completely before slicing.