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