Preheat oven to 350 F. Line an 8 x8-inch baking pan with parchment paper.

In the bowl of a stand mixer, cream the butter and brown sugar together for 2 minutes on medium speed.

Add the egg, vanilla, baking powder, and salt. Mix until just combined, then scrape down sides of the bowl.

Add the flour, mix on low speed until just combined. Stir in the white chocolate chips and 1/2 cup sprinkles.

Press the dough into the prepared pan, then top with the additional 2 tablespoons of sprinkles.

Bake for 20 to 25 minutes or until lightly golden brown around the edges.

Let them cool in the pan on a wire rack

These bars will keep for 3 days tightly wrapped or could be frozen for longer storage.