01 - Beat softened butter and powdered sugar in large bowl until light and fluffy.
02 - Mix in lemon juice, lemon zest, and vanilla extract until fully incorporated.
03 - Add salt, flour, and cornstarch, mixing until soft dough forms.
04 - Divide dough in half, roll into 1-inch diameter logs, wrap in plastic, and refrigerate 30 minutes.
05 - Preheat oven to 350°F and line baking sheets with parchment paper.
06 - Cut chilled dough into 1/4-inch rounds and place on prepared sheets 1 inch apart.
07 - Bake 10-12 minutes until edges are barely golden.
08 - Let cool 5 minutes on sheets, then gently toss in powdered sugar while warm.
09 - Transfer to wire rack and cool completely before serving with additional dusting.