Key Lime Pie Sandwich Cookies

Step 1
Preheat the oven to 375 degrees F (190 degrees C). Line 2 baking sheets with parchment paper.

Step 2
Combine flour, graham cracker crumbs, baking soda, baking powder, and cinnamon in a bowl.

Step 3
Cream butter and 1/2 cup sugar together in a bowl with an electric mixer. Add egg yolk and vanilla; blend until combined. Mix in dry ingredients and continue to blend until dough sticks together, 1 to 2 minutes.

Step 4
Roll dough into 1-inch balls and roll in remaining sugar to coat. Place on the prepared baking sheets.

Step 5
Bake in the preheated oven until bottoms are lightly browned, 6 to 7 minutes. Cool on the baking sheets for 5 minutes before removing to a wire rack to cool, 8 to 10 minutes more.

Step 6
Zest all 3 limes; set zest aside. Juice 2 of the limes.

Step 7
Beat cream cheese in a bowl with an electric mixer until smooth. Mix in confectioners' sugar. Add lime juice and zest; mix to combine.

Step 8
Spread filling on the flat sides of 1/2 of the cookies, then top with remaining cookies to form sandwich cookies.