Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking pan or line it with parchment paper.

In a medium saucepan, melt the unsalted butter over low heat. Remove from heat and allow to cool slightly.

Stir the granulated sugar into the melted butter until well combined.

Add the eggs, one at a time, mixing well after each addition. Stir in the vanilla extract.

In a separate bowl, whisk together the flour, cocoa powder, salt, and baking powder. Gradually fold the dry ingredients into the wet ingredients until just combined.

Pour the brownie batter into the prepared pan and spread it evenly. Bake for 20-25 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.

Let the brownies cool in the pan before cutting them into squares.