Preheat the oven to 350 ℉. Line two cookie sheets with parchment paper, baking mat, or spray with cooking spray. * I recommend using parchment paper for the best results. Helps the cookies bake evenly and prevents the bottoms from getting browned.
In a small bowl whisk together the flour, baking soda, and salt. Set aside.
1 cup all-purpose flour, ½ teaspoon baking soda, ¼ teaspoon salt
In a mixing bowl with an electric hand mixer, or use a stand mixer, beat the butter, peanut butter, sugar, and brown sugar on medium speed until combined and creamy. * The mixture should be much lighter in color and look fluffy and creamy. About 1-2 minutes.
4 tablespoons butter, 1/2 cup creamy peanut butter, 1/2 cup granulated sugar, 1/2 cup light brown sugar
Add in the egg and vanilla extract. Beat just until combined.
1 large egg, 1 teaspoon vanilla extract
Add the dry ingredients into the peanut butter mixture and beat on low speed just until combined and no flour streaks remain. * It's important to not over-beat the dough once you add the dry ingredients. Just mix until incorporated and no flour streaks remain in the dough.
Stir in 1 cup of the Reese's Pieces until combined into the dough.
1½ cups Reese's Pieces
Use a medium cookie scoop to scoop the dough and place it onto the prepared cookie sheet. * Place 12 cookie dough balls per cookie sheet.
Press the remaining 1/2 cup of Reese's Pieces by placing a few on top of each cookie dough ball.
Bake for 9-12 minutes or just until the edges of the cookies are set and starting to turn very lightly golden brown.
Let the cookies cool for 10 minutes on the warm cookie sheet before transferring them to a cooling rack to cool completely.
Notes
Add-Ins : Use any add-ins you want, just make sure that they equal 1.5 cups total. I like to use half Reese's Pieces + half Reese's Peanut Butter Cups (with Reese's Pieces in them) when I make these cookies. You can also use peanut butter chips, milk chocolate chips, white chocolate chips + White Reese's Peanut butter cups, etc. Lots of options!Make Big Cookies : For a giant cookie use a large cookie scoop (about 3-4 tablespoons of dough). You may want to lightly smoosh the cookie dough ball down with the bottom of a cup to ensure it bakes up properly. It should look like a hockey puck shape when done. Add 2-3 minutes of additional bake time. Peanut Butter : I only recommend using regular creamy peanut butter and not the varieties that are "no-stir" or "all-natural". They tend to make baked goods like cookies, very dense and dry. You can try substituting crunchy peanut butter. I've never done it but I think it would work just fine.