Preheat oven to 350°F.
Line a 9×9 pan with nonstick foil.
Beat butter, peanut butter and sugars together until creamy.
Add eggs, vanilla, salt.
Turn the mixer to low and mix in the baking soda and flour until just combined.
Fold in half of the peanut butter cups.
Spread batter into pan and press the rest of the pb cups into the batter.
Bake for only 20 mins.
Do not over bake!
Cool completely and cut into bars.