In a large bowl at low speed, beat butter until creamy looking. Add powdered sugar; mix until light and fluffy. Add lemon zest and lemon juice; beat well. Add flour and cornstarch into butter mixture and mix well until well combined.
Divide dough in half and shape each half into 8" x 1" rolls. Wrap each individual roll in plastic wrap. Refrigerate until firm, approximately 1 to 2 hours.
Preheat oven to 350 degrees F.
Using a sharp knife, cut each roll into 1/4-inch slices. Place cookie slices onto ungreased cookie sheets, place 2 inches apart on cookie sheet, and bake approximately 8 to 12 minutes or until bottoms are light brown (tops should not brown).
Remove from oven, carefully remove from baking sheet, and cool on wire cooling racks (when warm the cookies are delicate).
When cool, spread Lemon Frosting onto top of cookies.
In a medium bowl, combine butter, lemon zest, lemon juice, and powdered sugar; stir until well mixed.
NOTE: Additional lemon juice may be needed to get the frosting thin enough.
* Very important - please use room temperature butter (not softened or melted butter).
Lemon Melt Away Cookie Recipe: https://whatscookingamerica.net/cookie/lemonmeltawaycookie.htm