Melt the unsalted butter and chocolate chips in a saucepan over low heat, stirring constantly until smooth (about 3-5 minutes). Remove from heat and let cool for 10-15 minutes.
In a large bowl, beat the white sugar and eggs until well combined. Stir in the all-purpose flour, baking powder, and vanilla extract.
Bake in the preheated oven for 30-35 minutes until a toothpick inserted in the center comes out clean or with a few moist crumbs.