In a food processor, pulse together flour, confectioners sugar, salt and lemon zest until combined.
Add butter and process until crumbly.
Add in egg yolks and lemon juice and pulse util dough comes together.
Divide dough in half and form into two logs.
Wrap in wax paper and refrigerate or freeze until firm. (a couple of hours up to a month)
Preheat oven to 350 degrees F.
Roll log of dough into sugar, coating the outside.
Slice logs into 1/4 inch thick slices and arrange on parchment lined cookie sheet.
Bake until gold brown around the edges, 12-15 minutes.
Transfer cookies to rack to cool.