01 - Preheat oven to 350°F and line a baking sheet with parchment paper.
02 - In a large bowl, beat softened butter and granulated sugar until light and fluffy, approximately 2-3 minutes.
03 - Mix in egg yolk and vanilla extract until fully incorporated.
04 - Gradually blend in all-purpose flour and salt, mixing just until dough comes together. Avoid overmixing.
05 - Roll dough into 1-inch balls and arrange on prepared baking sheet, spacing 2 inches apart.
06 - Gently press your thumb or the back of a spoon into the center of each dough ball to form a well.
07 - Spoon approximately 1/2 teaspoon of lemon curd into each indentation, being careful not to overfill.
08 - Bake for 10-12 minutes until edges begin to turn light golden brown. Centers should remain slightly soft.
09 - Let cookies rest on baking sheet for 5 minutes, then transfer to wire rack to cool fully before serving.
10 - Lightly dust cooled cookies with powdered sugar just before serving, if desired.