Preheat the oven to 350°F (175°C).

Grease a 9x13-inch baking pan.

In a large bowl, mix the melted butter and sugar until well combined.

Add the eggs one at a time, mixing well after each addition.

Stir in the vanilla extract.

In another bowl, whisk together the flour, cocoa powder, salt, and baking powder.

Gradually add the dry ingredients to the wet mixture, stirring until just combined.

Pour the brownie batter into the prepared pan and spread evenly.

Bake for 25-30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.

Allow the brownies to cool completely in the pan.

Once cooled, use a star-shaped cookie cutter to cut out star shapes from the brownies.

Decorate with red and blue sprinkles or colored sugar.