Preheat the oven to 375 degrees. Prepare two mini-muffin pans with nonstick cooking spray.
Whisk together the flour, baking soda, and salt.
In a large mixing bowl, beat the butter, brown sugar, and white sugar until fluffy
Add the peanut butter and mix until well blended. Add the eggs and vanilla, beating until fully incorporated.
Slowly add the flour mixture to the peanut butter mixture, scraping down the sides if needed.
Using a small cookie scoop, portion the dough into 1 inch balls and drop into the wells of the prepared mini-muffin pans.
Bake for 8 to 10 minutes.
Remove the cookies from the oven and immediately press a mini Reese’s peanut butter cup into each cookie’s center.
Allow the cookies to cool completely before removing them from the pans. To remove, use a butter knife or spoon to lift from the sides of the cookie.