Design Eat Repeat

6 Preheat oven to 350°F.
0 In a large bowl, cream together softened unsalted butter (¾ cup, i.e., 1 ½ sticks), peanut butter (1 cup), light brown sugar (1 cup), and granulated sugar (1 cup) with an electric mixer on medium speed for 30 seconds. Add in vanilla extract (1 teaspoon) and eggs (2 large) and continue to mix for 10 seconds.
1 Add baking soda (1 ½ teaspoons) and mix on low speed for 10 seconds. Add all-purpose flour (2 ½ cups) and continue to mix until all flour is incorporated.
2 Scoop & roll dough into 1 tablespoon sized balls and place each in a greased, mini muffin tin.
3 Bake at 350℉ for 8 minutes. The trick to making these super soft is to only bake them for 8 minutes. A minute or two longer and you'll have a crunchy, brown cookie (which isn't bad if you like crunchy cookies, but I like mine soft!). If baking the large version of these cookies (3-tablespoon flattened balls, bake for 9-11 minutes).
7 Remove from oven, and immediately press one mini Reeses peanut butter cup into the center of each cookie. 
4 After inserting the Reeses, allow the cookies to cool on a cooling rack (while still in the muffin pan) for about 20 minutes. At this point, your chocolate will likely still be melted so you should then place the entire pan in the fridge for about 15 minutes or until the chocolate sets. Once the chocolate is hardened, use a spoon to gently "scoop" out the cookies. This is where spraying the muffin tin before baking is crucial, otherwise your cookies will stick to the pan!
5 If not serving immediately, store in an airtight container for up to 5 days or freeze for long-term storing.