1. Preheat the oven to 350°F and line a 9×13-inch baking pan with parchment paper.

2. Beat the softened butter, granulated sugar, and brown sugar together until creamy and smooth.

3. Add the eggs one at a time, then mix in the vanilla extract.

4. In a separate bowl, whisk together the flour, cocoa powder, baking powder, and salt.

5. Add the dry ingredients to the butter mixture and mix just until a soft dough forms.

6. Fold in the white chocolate chips, then press the dough evenly into the prepared pan.

7. Bake for 22 to 26 minutes, or until the edges are set and the center no longer looks wet.

8. Let the bars cool completely in the pan.

9. Warm the heavy cream until steaming, then pour it over the semi-sweet chocolate chips.

10. Let the mixture sit for 2 minutes, then stir until smooth and glossy.

11. Spread the chocolate topping over the cooled bars and add chocolate sprinkles.

12. Chill briefly for cleaner slices, then cut into squares and serve.