Preheat oven to 350 degrees F. Grease a 9 x 13 pan with cooking spray or line with parchment paper.
In a large bowl, beat together butter, peanut butter and sugars. Beat until light and fluffy.
Add in eggs and vanilla, stir until combined.
In another bowl, mix together flour, salt and baking soda. Add dry ingredients to wet ingredients and mix until just combined.
Place batter into prepared pan.
Press Reese's peanut butter cups into batter. Place in a 4 x 7 row. Bake 25-30 minutes or until golden brown.
Cool and then drizzle with melted chocolate and peanut butter. Allow to set up before cutting.
Notes
Substitute for Peanut Butter:If you are allergic or don't like peanut butter you can substitute in your favorite nut butter such as almond butter or cashew butter. How to Store Peanut Butter Blondies:Keep any leftovers covered and stored in the refrigerator for 3-4 days. You can also freeze them for up to 3 months in an airtight container or wrapped in plastic wrap and foil.