Step 1

Beat butter, sugar, zest and vanilla until light and fluffy. Add egg yolks and stir just until blended.

Step 2

Mix together flour and salt. Add to butter mixture and mix just until blended.

Step 3

Divide dough in half and roll into cylinders (about a foot long). Place in refrigerator for two hours or up to five days.

Step 4

Preheat oven to 350F.

Step 5

Remove dough from fridge and unwrap. Slice into circles about 1/4 inch thick and place on parchment-lined baking sheets. Bake for 15-18 minutes or until just starting to turn golden brown around the edges. Remove immediately to wire racks and let cool completely.

Step 6

Once cookies are completely cooled, mix together the powdered sugar and lemon juice. Drizzle or spread over cookies.