01 - Preheat oven to 350°F and line a baking sheet with parchment paper.
02 - In a large bowl, beat butter and sugar until light and fluffy.
03 - Mix in egg yolk and vanilla extract until fully incorporated.
04 - Gradually blend in flour and salt until dough just comes together.
05 - Roll dough into 1-inch balls and place on prepared baking sheet, spacing 2 inches apart.
06 - Press thumb or spoon gently into center of each ball to form a well.
07 - Fill each indentation with approximately 1/2 teaspoon lemon curd.
08 - Bake for 10-12 minutes until edges begin to turn golden brown.
09 - Let cool on baking sheet for 5 minutes, then transfer to wire rack. Dust with powdered sugar before serving if desired.