Preheat oven to 350°F. Line a cookie sheet with parchment paper.
Mix Wet Ingredients: In a large bowl, cream the softened butter and sugar until light and fluffy using an electric mixer or sturdy spatula. Add the egg, vanilla extract, and lemon extract, and mix until well incorporated.
1 cup unsalted butter, 1 cup granulated sugar, 1 large egg, 1 teaspoon vanilla extract, ½ teaspoon lemon extract
Add Dry Ingredients: Whisk flour and salt together in a small bowl and then add to the wet ingredients. Mix gently until a soft dough forms. Wrap the dough in plastic wrap and refrigerate for at least 1 hour to firm up.
2 ½ cups all-purpose flour, ½ teaspoon salt
Form Balls of Dough: Use a cookie scoop to roll the chilled dough into 1-inch balls and place them on the prepared baking sheet, spacing them about 2 inches apart in a single layer. Use your thumb or the back of a spoon to create small indentations in the center of each ball.
Bake and Cool: Bake the cookies for 8–10 minutes, or until the edges are lightly golden but not brown. Remove from the oven and let the cookies cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.
Dust with Sugar and Fill with Lemon Curd: Once the cookies are completely cool, add powdered sugar in a fine mesh strainer and dust buttery cookies around the edges. Spoon the lemon curd filling into each indentation, or pipe it with a bag.
¼ cup powdered sugar, 1 cup lemon curd
Notes
Don’t skip chilling the dough, it helps the cookies maintain their shape during baking and prevents excessive spreading.
If the indentation loses shape during baking, press it gently with a spoon as soon as the cookies come out of the oven.
For neat and precise filling, use a piping bag or a zip-top bag with the corner snipped off to add the lemon curd to the cookies.
You can freeze the cookie dough before baking for up to 3 months in a freezer-safe container. Thaw in the refrigerator overnight before making cookies as directed.Dust the cookies with powdered sugar or drizzle with a lemon glaze if desired.
Store the cookies in an airtight container in the refrigerator for up to 5 days to keep the cookies fresh. Arrange in a single layer.