Mix powdered sugar, butter, vanilla, lemon juice and egg in large mixing bowl. Stir in flour, baking soda, cream of tartar, lemon zest and rosemary until combined. Cover and refrigerate for at least 1 hour
Preheat oven to 375 degrees. Line a cookie sheet with parchment paper and spray lightly with cooking spray. Set aside.
Form 1" balls with dough and place on prepared cookie sheet. Moisten the bottom of a glass and lightly press the cookie flat. Repeat with remaining dough.
Combine lemon zest and sugar then sprinkle over each cookie.
Bake for 7-8 minutes and let cool completely.
Drizzle cooled cookies with glaze and enjoy!
Notes
These are the best cookies EVER. We couldn't quit eating the dough!