Preheat oven to 375º F. Line baking sheet with parchment paper and set aside.
In a medium bowl, whisk together flour, baking soda and salt. Set aside.
In the bowl of a stand mixer (or using a hand mixer and a large bowl), combine 1/2 cup granulated sugar, brown sugar, butter, and peanut butter. Beat until combined and fluffy, about 2 minutes. Scrape down the sides when necessary. Add egg and vanilla. Beating until mixed, about 30 seconds.
With the mixer on low, slowly add the flour mixture and beat just until combined.
Scoop 2 Tablespoons of dough and flatten it into a disc. Place a marshmallow half in the center, then wrap the dough around it. Roll into a ball and place on the parchment-lined baking sheet. Gently press a few peanut butter chips on top. Repeat with remaining dough, placing each ball of dough 2 inches apart on the baking sheet.
Bake at 375℉ for 10 to 12 minutes or until the edges are turning golden in color. Cool on the pan for a few minutes, then transfer to a wire cooling rack to cool completely.
Notes
No-stir peanut butter is essential for the consistency in this cookie dough. Do not use peanut butter that separates in the jar with oil on top.Marshmallow halves are the least messy method to make these cookies. You can also use 5 mini marshmallows or 2 teaspoons of marshmallow fluff if preferred.Store in an airtight container at room temperature for up to 3 days.Freeze baked cookies for up to 2 months. Freeze cookie dough (without marshmallows) for up to 3 months.