Ingredients
Scale
- 1/2 cup 1 stick unsalted butter, softened
- 1/2 cup peanut butter
- 3/4 cup light brown sugar (packed)
- 1/4 cup granulated sugar
- 1 large egg
- 2 teaspoons vanilla extract
- 2 cups all-purpose flour
- 2 teaspoons cornstarch
- 1 teaspoon baking soda
- 1/4 teaspoon kosher salt
- 1 1/2 cups peanut butter M&Ms (or another variety of M&Ms, or chocolate chips may be substituted)
Instructions
- In the bowl of a stand mixer fitted with the paddle attachment, combine the butter, peanut butter, sugars, egg, vanilla, and beat on medium speed (I used 6 on my Kitchen Aid stand mixer) until well-creamed, light and fluffy, about 5 minutes (or use a hand mixer and beat for at least 7 minutes). Stop, scrape down the sides of the bowl, and add the flour, cornstarch, baking soda, salt, and mix until just combined, about 1 minute. Add the M&Ms and fold in by hand (Don’t try and do this with the mixer – the M&M’s will break!)
- Using a medium 2-inch cookie scoop, form heaping mounds (each ball should be about 2 ounces). Place mounds on a large plate, flatten mounds very slightly with your palm, cover with plasticwrap, and refrigerate for at least 2 hours, or up to 5 days, before baking. Do not bake with warm dough because cookies will spread.
- Preheat oven to 350F, line a baking sheet with a Silpat Non-Stick Baking Mat or parchment paper. Place the cookies on the baking sheet, spaced at least 2 inches apart.
- Bake for 10-13 minutes, until just set (mine were good at 10, 13 produces a crunchier cookie). Allow cookies to cool on the baking sheet for 5 minutes before removing and transferring to a rack to finish cooling.
- Store cookies in an airtight container at room temperature for up to 1 week, or in the freezer for up to 3 months. Unbaked cookie dough can be stored in an airtight container in the refrigerator for up to 5 days, or up to 3 months in the freezer.