01 - Preheat oven to 350°F and line baking sheet with parchment paper.
02 - In a large bowl, beat softened butter and granulated sugar until light and fluffy using electric mixer or whisk.
03 - Mix in egg yolk and vanilla extract until fully incorporated.
04 - Gradually blend in flour and salt until dough just comes together. Do not overmix.
05 - Roll dough into 1-inch balls and place on prepared baking sheet, spacing 2 inches apart.
06 - Press thumb or back of spoon into center of each ball to form a deep well.
07 - Spoon approximately 1/2 teaspoon lemon curd into each indentation.
08 - Bake for 10-12 minutes until edges are just beginning to turn golden brown.
09 - Let cookies rest on baking sheet for 5 minutes, then transfer to wire rack to cool completely.
10 - Lightly dust cooled cookies with powdered sugar before serving.