01 - Cream the softened butter and 1/2 cup powdered sugar in a large bowl until mixture becomes light and fluffy, approximately 2-3 minutes.
02 - Blend in fresh lemon juice, lemon zest, and vanilla extract until fully incorporated into the butter mixture.
03 - Add salt, flour, and cornstarch to the bowl. Mix on low speed until a soft, cohesive dough forms, taking care not to overmix.
04 - Divide dough into two equal portions. Roll each portion into a 1-inch diameter log. Wrap tightly in plastic wrap and refrigerate for at least 30 minutes or until firm enough to slice cleanly.
05 - Set oven temperature to 350°F. Line two baking sheets with parchment paper and set aside.
06 - Remove dough logs from refrigerator and unwrap. Slice into 1/4-inch thick rounds using a sharp knife. Arrange slices on prepared baking sheets, leaving 1 inch of space between cookies.
07 - Place baking sheets in preheated oven and bake for 10-12 minutes, watching closely until edges develop a very light golden color. Centers should remain pale.
08 - Let cookies rest on baking sheets for 5 minutes after removing from oven. While still warm, gently roll each cookie in powdered sugar to coat evenly.
09 - Transfer coated cookies to a wire cooling rack and allow to cool completely. For enhanced presentation, dust with an additional layer of powdered sugar immediately before serving.