Preheat oven to 350 F. Line baking sheets with parchment paper.

In a small bowl, combine flour, baking powder, and salt.

In a medium bowl, combine sugar and lemon zest. Rub together until fragrant.

Add butter to lemon sugar mixture and beat until light and fluffy. Beat in egg and vanilla until smooth.

On low speed, beat in flour mixture. Drop dough by the tablespoon onto prepared baking sheets. Gently flatten each drop of dough with the palm of your hand.

Bake 12-14 minutes or until cookies are just set and slightly golden brown. Cool on baking sheet for 2 minutes before transferring to wire rack to cool completely.

Whisk together powdered sugar and lemon juice. Separate a small amount of glaze and add a few drops of yellow food coloring. Place yellow glaze into a piping bag with a small round tip.

Dip cookies into white glaze and let set. Using the piping bag, pipe small Mickey Mouse ears on each cookie and let dry completely.