If you love peanut butter, add these peanut butter marshmallow sandwich cookies to your baking repertoire. They’re a one-bowl, four-ingredient cookie that comes together in about 20 minutes, with a fluffy marshmallow frosting sandwiched in the center. Because the cookie base is flourless, this recipe is naturally gluten-free when made with gluten-free peanut butter and sugar.
Peanut Butter & Marshmallow Sandwich Cookies
These cookies are fast, simple, and surprisingly crowd-pleasing. They were a hit with my family — even with a child who isn’t particularly fond of sweets — so they’re a great option when you need a reliable, kid-approved treat. The cookie itself is classic peanut butter: rich, slightly salty, and chewier than a traditional butter cookie. The marshmallow frosting adds a light, pillowy contrast that turns each bite into a delightful sandwich cookie.
Because the cookie dough requires just a few pantry staples and no flour, they’re easy to whip up on short notice. If you prefer an even quicker shortcut, store-bought marshmallow fluff can replace the homemade frosting without sacrificing flavor.
Peanut Butter & Marshmallow Sandwich Cookies
Ingredients
- 1 cup natural peanut butter, smooth or crunchy
- 1 cup sugar
- 1 large egg, lightly beaten
- 1 teaspoon vanilla extract
Marshmallow Frosting
- 5 large egg whites
- 1 1/2 cup sugar
Instructions
Preparation
Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper.
- To make the peanut butter cookies: Combine the peanut butter, sugar, egg, and vanilla in the bowl of a stand mixer or a large mixing bowl. Mix on low until just combined. Use a cookie scoop to portion about 1 1/2 tablespoons of dough onto the prepared baking sheet, spacing cookies an inch apart. Flatten each cookie with a fork in a criss-cross pattern. Bake for 10–12 minutes, or until edges are lightly golden. Allow cookies to rest on the baking sheet for 2 minutes, then transfer to a cooling rack.
- To make the marshmallow frosting: Combine the egg whites and sugar in a heatproof mixing bowl set over (not touching) simmering water, like a bain-marie. Whisk constantly until the mixture reaches 160°F (71°C) and the sugar is dissolved. Remove the bowl from the heat and transfer to a stand mixer fitted with the whisk attachment. Beat on medium-high speed until the mixture cools, doubles in volume, and forms stiff peaks, about 10–12 minutes.
- Optional: For a shortcut, use store-bought marshmallow fluff in place of the homemade frosting.