In a medium sauce pan, melt the butter over medium high heat. Add the sugar and cocoa powder once the butter is melted. Whisk to combine and remove from heat.
Add the salt, vanilla, and eggs and continuously whisk until the eggs are combined. Add the baking powder and flour and continue to mix. Add in your chopped up leftover candy. Stir until incorporated.
Transfer to a greased 12 inch cast iron skillet. Drizzle the caramel on top, and drag a knife through the caramel to spread the caramel throughout the brownie.
Transfer to the oven and bake for 35 - 40 minutes until done. Once the brownie is removed from the oven, place additional candy pieces on top for presentation.