Preheat the oven to 350°.
Line 9x13 pan with nonstick foil.
Melt butter and chips in microwave safe bowl.
Whisk in sugars.
Add the eggs one at a time.
Add vanilla.
Fold in dry ingredients.
Pour in pan and press peanut butter cups into the batter.
Bake approx 30 mins.
Once cool, melt peanut butter in the microwave and drizzle on top.
Cut into squares.