Key Lime Sandwich Cookies
These Key Lime Sandwich Cookies are a little bite of sunshine! Buttery key lime cookies are sandwiched together with a fluffy layer of Key Lime Marshmallow Buttercream for the perfect sweet and citrusy treat. They are fun to make, fun to share, and even more fun to eat!
Servings: 17 sandwich cookies
Calories: 348kcal
Ingredients
Cookies
- 1 cup (2 sticks / 227 g) unsalted butter, softened
- ¾ cup (90 g) confectioners' sugar
- ½ teaspoon kosher salt
- 1 tablespoon fresh key lime zest
- 2 tablespoons key lime juice
- ½ teaspoon vanilla extract
- 2 ¼ cups (280 g) all-purpose flour
Key Lime Marshmallow Buttercream
- ¼ cup (½ stick / 57 g) unsalted butter, room temperature
- ½ jar (3 ½ ounces) marshmallow creme (marshmallow fluff)
- 2 ounces cream cheese, room temperature
- 2 cups confectioners' sugar
- ½ to 1 tablespoon key lime juice
- ½ teaspoon key lime zest
- 1 pinch kosher salt
- ¼ teaspoon vanilla extract
Instructions
Cookies
- Preheat oven to 375°F. Line baking sheets with parchment paper.
- In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, confectioners' sugar, salt, and key lime zest until smooth and creamy.
- Add the key lime juice and vanilla extract and mix until combined.
- Gradually add the flour and mix just until a soft dough forms.
- Scoop the dough into 1-tablespoon portions. Roll each portion into a ball, then flatten to about ¼-inch thick using the bottom of a glass.
- Bake for 9 to 12 minutes, or until the cookies are set and the edges begin to turn golden. Let the cookies cool completely before filling.
Key Lime Marshmallow Buttercream
- In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and cream cheese until smooth and creamy, about 2 minutes.
- Add the marshmallow creme and mix until fully incorporated.
- With the mixer on low speed, gradually add the confectioners' sugar, mixing until smooth.
- Add ½ tablespoon of key lime juice, key lime zest, salt, and vanilla extract. Mix until combined.
- Taste and add more key lime juice, if desired, until the frosting reaches your preferred balance of sweetness and citrus flavor.
- Increase the mixer speed to medium-high and beat for 1 to 2 minutes, or until light and fluffy.
Assemble Cookies
- Pipe or spread about 1 to 2 tablespoons of Key Lime Marshmallow Buttercream onto the flat side of one cookie.
- Top with another cookie and gently press together.
- Repeat with the remaining cookies. For cleaner edges and a firmer filling, chill the assembled sandwich cookies for 20 to 30 minutes before serving.
Nutrition
Serving: 1sandwich cookie | Calories: 348kcal