Preheat your oven to 350°F (175°C). Grease and flour a square baking pan or line it with parchment paper for easier removal.

Melt the butter over low heat and allow it to cool slightly.

In a mixing bowl, combine the sugar, eggs, and vanilla extract. Mix until smooth and creamy.

Slowly beat in the melted butter until fully incorporated.

Add the cocoa powder, flour, salt, and baking powder to the mixture, stirring until just combined.

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

Bake in the preheated oven for 20-25 minutes. To check if done, insert a toothpick into the center; it should come out with moist crumbs.

Let the brownies cool in the pan, then transfer them to a cutting board. Use a heart-shaped cookie cutter to cut them into adorable shapes.