Lemon Sandwich Cookies

Adapted from Fresh

Cookies
2 cups all purpose flour
2 teaspoons baking powder
¾ teaspoon salt
¾ cup (1 ½ sticks; 12 tablespoons) unsalted butter, at room temperature
1 cup white sugar
½ cup powdered sugar
1 egg
¼ cup sour cream
1 tablespoon lemon juice
2 teaspoons lemon zest

1. In a medium bowl, combine the flour, baking powder, and salt.
2. In a large bowl, use an electric mixer to beat together the butter, white sugar, and powdered sugar until well combined. Add the egg, sour cream, lemon juice, and lemon zest; beat for 3 minutes.
3. Stir in the flour mixture until well combined.
4. Heat oven to 375 degrees. Line two baking sheets with parchment paper.
5. Take a teaspoon of dough and roll it into a ball; place on prepared baking sheet. Repeat until dough is used up, placing the dough balls 2 inches apart (they will spread during baking).
6. Bake cookies 12-14 minutes; the edges should be lightly browned. Let cool.

Filling
4 cups powdered sugar
¼ cup (½ stick; 4 tablespoons) unsalted butter, at room temperature
6 tablespoons heavy cream
3 teaspoons lemon zest

1. In a large bowl, beat together the powdered sugar, butter, heavy cream, and lemon zest until the mixture is thick and well blended (this will take about 3 minutes).
2. When the cookies have cooled, assemble cookie sandwiches by placing filling on the flatter side of a cookie and placing another cookie, flatter side down, on top. Repeat until all of the cookies are sandwiched.