Preheat the oven to 350˚F.

If you'd like, line baking sheets with silicone baking mats or parchment paper. If not, just use ungreased baking sheets.

In the bowl of an electric mixer, combine the butter and peanut butter. Beat on medium-high speed until smooth creamy, about 2 minutes.

Add in the granulated sugar, brown sugar, baking soda, and baking powder. Beat till combined, scraping sides of bowl as needed.

Beat in the eggs and vanilla until combined.

Add in the flour, a cup at a time, and mix until combined.

Add in the chopped peanut butter cups and fold in gently with a spatula.

Drop small rounds (appx. 1-1/2 inch balls) of dough onto the baking sheets, spacing 2 inches apart.

Bake 7-9 minutes (every oven is different, so just keep an eye on them). You want the cookies to be very soft and slightly under-baked immediately coming out of the oven, they will set as they cool. (Do not over bake your cookies - this will make or break this recipe, so don't over-bake!)

Let cool on the baking sheet for a few minutes, then transfer to a wire rack to cool completely.

Store in an airtight container. I like to store my cookies in the freezer in ziploc freezer bags.

Makes 3-4 dozen cookies.