Preheat oven to 350F and line a 9x13 pan with foil or parchment paper

In a stand mixer with a paddle attachment, combine melted butter and sugars and beat until smooth

Add eggs and yolk one at a time, beating until combined, then add vanilla

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

With the mixer on low, slowly add the flour mixture to the butter and sugar mixture until just combined. DO NOT OVERMIX! Stir in chocolate chips, pretzels, and caramel bits

Spread batter into prepared pan and bake for 25-30 minutes

Cool on a wire rack.