Preheat the oven to 350°F. Line a 9x13 inch dish with parchment paper and spray with baking spray.

Melt the butter, then let it cool for a few minutes. In a large bowl, stir the melted butter, brown sugar, and granulated sugar together until combined. Add the eggs and vanilla and stir until smooth.

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

Add the dry ingredients to the wet along with 1 ½ cups of the chocolate chips and half of the sprinkles. Stir until just combined.

Spread the batter evenly into the prepared pan. Sprinkle the remaining ½ cup chocolate chips and the rest of the sprinkles over the top. These Halloween cookie bars bake up soft in the middle with slightly crisp edges.

Bake for 26 to 28 minutes, until the edges are golden and the center looks set.

Let the bars cool in the pan for at least an hour before slicing. The full hour keeps these Halloween cookie bars from crumbling when you cut them.