Preheat the oven to 350°F (175°C). Grease a 9x9-inch baking pan.

In a mixing bowl, combine the melted butter and sugar until well blended.

Add the eggs and vanilla extract, stirring until fully combined.

Sift together the cocoa powder, flour, salt, and baking powder. Gradually mix this into the wet ingredients until just combined.

If you're feeling extra indulgent, fold in the chocolate chips.

Pour the batter into the prepared baking pan, spreading it evenly.

Bake for 20-25 minutes or until a toothpick inserted in the center comes out slightly moist (but not wet!).

Let them cool before cutting into squares.

Serve warm with a scoop of vanilla ice cream or as desired.