Preheat the oven to 350°F (175°C). Grease a 9x13-inch baking pan.
In a large mixing bowl, combine the melted butter and granulated sugar. Mix 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 add the dry ingredients to the wet mixture, stirring until just combined.
Fold in the white chocolate chips. Pour the brownie batter into the prepared baking pan and spread evenly.
Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
Allow the brownies to cool completely in the pan. Once cooled, use the star-shaped cookie cutter to cut out star shapes from the brownies.
Sprinkle red and blue sprinkles on top of the star brownies for a festive touch.