Preheat your oven to 350 degrees. Prepare an 8 x 8 or 9 x 9 inch pan with cooking spray. Set aside.
In a medium sized bowl melt butter in microwave and set aside.
Combine flour, sugar, cocoa powder, salt and baking powder in a large bowl. Set aside.
In a medium bowl, beat the eggs with the vanilla and add to the dry ingredients. Add the melted butter and mix until just combined. Spread ½ of the batter into your prepared pan and bake for 11 minutes.
Place caramel bits in a small saucepan on medium-low. Add milk and stir until all of the caramel bits are melted, approximately 5 minutes. Remove from heat. Add 1 teaspoon vanilla and stir until combined.
After 11 minutes, remove brownie from your oven and evenly distribute peanut butter chips on top. Pour caramel sauce as evenly as possible over top of the peanut butter chips. Pour remaining batter over top of caramel sauce. Bake for 18-20 minutes, or until edges start to darken. Remove from your oven and allow to totally cool, between 4 or 5 hours. Yes, that long. I have served it a little earlier but do your best to wait! It is totally worth it! Serve with toppings of your choice! You will enjoy this dessert!