01 - Beat softened butter with powdered sugar until pale and fluffy.
02 - Blend in lemon juice, zest, and vanilla extract until fully incorporated.
03 - Mix in salt, flour, and cornstarch until soft dough comes together.
04 - Divide dough in half, roll into 1-inch diameter logs, wrap in plastic, and refrigerate 30 minutes.
05 - Heat oven to 350°F. Line baking sheets with parchment paper.
06 - Unwrap dough and cut into 1/4-inch rounds. Place 1 inch apart on prepared sheets.
07 - Bake 10-12 minutes until edges are lightly golden.
08 - Cool 5 minutes on sheets, then toss warm cookies in powdered sugar.
09 - Transfer to wire rack to cool completely. Dust with extra powdered sugar before serving.