Preheat your oven to 350°F (175°C). Grease the baking pan or line it with parchment paper for easier removal later.
In a medium saucepan, melt the butter over low heat. Once melted, remove from heat and stir in the granulated sugar until well combined.
Allow the butter and sugar mixture to cool slightly, then add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
In a separate bowl, sift together the flour, cocoa powder, salt, and baking powder. Gradually add this dry mixture to the wet ingredients, stirring until just combined.
Fold in the semi-sweet chocolate chips.
Pour the brownie batter into the prepared baking pan, spreading it evenly.
Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.
Once baked, remove from the oven and allow to cool in the pan for at least 10 minutes before transferring to a wire rack to cool completely.
Once cooled, cut the brownies into 12 equal squares. Decorate the top with pastel candy-coated chocolates for a festive touch.