Description

These Key Lime Sandwich Cookies are the perfect combination of buttery cookies and a bright, tangy lime filling. Made with fresh key lime zest and juice, these sandwich cookies are soft, flavorful, and ideal for spring or summer gatherings. Whether you fill them with a zesty buttercream or a creamy key lime cream cheese frosting, they’re guaranteed to be a refreshing twist on a classic treat. Great for parties, gifting, or enjoying with a cold drink on a warm day.

Ingredients

Scale

Graham Cookies

1 cup butter, room temperature
1 1/2 cups light brown sugar
2 large eggs
2 teaspoons vanilla extract
2 cups graham cracker crumbs
1 teaspoon baking soda
1 teaspoon kosher salt
2 cups all-purpose flour

Key Lime Buttercream Filling

1/2 cup butter, room temperature
1 tablespoon lime zest
3 tablespoons freshly squeezed key lime juice
4 cups powdered sugar

Instructions

Cookies: Preheat the oven to 350°F. Line a baking sheet with parchment paper and set aside.
In the bowl of your stand mixer, fitted with the paddle attachment, mix the butter and sugar on medium speed for 2 minutes until light and fluffy. Turn the speed down slightly and add in eggs and vanilla, mixing until smooth, scraping the sides of the bowl as necessary.
With the mixer on medium-low speed, add in the graham cracker crumbs, baking soda, and salt, mixing until incorporated.
Turn the mixer speed to low and slowly add in flour until just combined.
Using a medium (2-tablespoon) cookie scoop, drop the dough about 2 inches apart onto the prepared baking sheet.
Bake cookies for 9 – 10 minutes until the edges are lightly golden.
Remove from the oven and allow the cookies to cool on the pan for 2 – 3 minutes, then transfer to a wire rack to cool completely.
Buttercream Filling: While the cookies are cooling, prepare the filling. In the bowl of the stand mixer fitted with paddle attachment, mix butter and zest until combined and smooth. Turn the mixer to low and slowly add in powdered sugar and key lime juice. Mix until combined, then turn the mixer to medium and beat for 1 – 2 minutes until creamy and smooth, scraping the sides of the bowl as necessary.
Turn half of the cookies upside down. Fill a piping bag (or a zip-top bag with the corner cut off) with key lime filling and pipe on approximately 2 tablespoons onto the bottoms of half of the cookies. Place the other half of the cookies on top of the filling, creating sandwiches.

Notes

Key Limes vs. Regular Limes: If you can’t find key limes, use Persian limes with a little extra zest and a splash of lemon juice to mimic the flavor.
Filling Options: Cream cheese frosting offers a tangier filling, while buttercream is more traditional and sweeter. Choose based on your taste preference.
Make Ahead: Cookies can be baked in advance and stored unfrosted in an airtight container for up to 3 days or frozen for up to 3 months.
Freezing: Freeze unassembled cookies and filling separately. Assembled cookies can be frozen individually wrapped.
Storage: Store assembled cookies in the fridge for 5–7 days. Bring to room temperature before serving.
Optional Add-Ins: Roll edges in toasted coconut, graham cracker crumbs, or drizzle with white chocolate for extra flair.