Preheat the oven to 350°F degrees. Spray a 24-count (or 2 12-count) mini muffin tin with nonstick spray and set aside.
Unwrap all of the Reese’s peanut butter cups.
24 Reese's miniature peanut butter cups
Whisk the flour, baking soda and salt in a medium bowl.
1 1/2 cups all purpose flour, 1 teaspoon baking soda, 1/2 teaspoon salt
In a large bowl using a electric mixer or a stand mixer fitted with the paddle attachment, beat the butter and peanut butter together until well combined, 1-2 minutes. Add the white sugar and brown sugar and beat until light and fluffy, at least 2-3 minutes.
1/2 cup unsalted butter, 3/4 cup creamy peanut butter, 1/3 cup granulated sugar, 1/3 cup packed light brown sugar
With the mixer on medium low speed, add the egg, milk and vanilla and beat until combined.
1 egg, 1 Tablespoon milk, 1 teaspoon vanilla extract
Turn the mixer on low and gradually add the dry ingredients, scraping down the bottom and sides of the bowl as needed. Continue to mix until full incorporated.
Place the extra cup of granulated sugar in a small bowl. Use a heaping teaspoon to scoop the dough and roll them into 1-inch balls. Roll each ball in the sugar and place them in the prepared muffin tin.
1 cup extra sugar
Bake them for 7-9 minutes, until puffed and slightly golden around the edges. Immediately press the unwrapped Reese’s peanut butter cups into the center of each cookie, so that the candy is inside and the cookie comes up and around the edges.
Cool them in the pan for 10 minutes then use a knife of fork to pop the cookies out of the tins and transfer them to a wire rack to cool completely. The Reese’s cups will melt and harden again as they cool.