These are cookies for all the peanut butter lovers out there! You can add whatever mix-ins you want! Like in our store we use this same base and add marshmallow fluff and dark chocolate for our flutternutter flavor. These bake into ridiculously delicious peanut butter cookies!
In a medium bowl, whisk together the flour, cornstarch, baking soda, and salt. Set aside.2.
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and peanut butter on medium speed until smooth and creamy, about 2 minutes. Add the granulated and brown sugars and mix on medium until light and fluffy; about 4 minutes will do the trick. Use a rubber spatula to scrape the bowl. Add the egg whites and vanilla and mix until fully incorporated, about 2 minutes.3.
Add half of the flour mixture and mix on low just until the powdery texture of the flour disappears, about 15 seconds. Immediately add the rest of the flour mixture and mix until combined. Scrape the bowl and mix a final 15 seconds.4.
Remove the bowl from the mixer and steal a lick right from the bowl. Make one of our signature combos. Use a rubber spatula to gently fold in the "fold" ingredients first. Then, if it calls for it, drop "swirl" mix-ins in tablespoon-size scoops in four different locations in the bowl. Use the rubber spatula to gently swirl until you see thick ribbons of that mix-in.5.
First, transfer your cookie dough to an airtight container or press a piece of plastic wrap onto the top of the cookie dough. Place in the refrigerator to chill for 24 hours. If you can't stand to wait, place in the freezer for at least 2 hours (this step helps your cookies hold their shape and gives you that nice gooey cookie center, so don't skip it!).6.
Once the dough is chilled, preheat the oven to 350°F. Line rimmed baking sheets with parchment paper or silicone baking mats. Use a cookie scoop to portion cold dough onto the baking sheets, leaving about 3 inches between scoops.7.
For soft-baked, gooey cookies, bake for 9-11 minutes, until the edges are lightly golden and the centers are just set. Check halfway through baking to ensure your cookies are cooking evenly. Rotate the baking sheet if needed. For crispier cookies, keep them in the oven for an additional 2-3 minutes, until the edges are golden brown.8.
Remove from the oven and let cool on the baking sheets for 5 minutes. Enjoy warm or transfer to a wire rack to cool completely.