Glazed Lemon Drop Cookies

Name: Glazed Lemon Drop Cookies
Prep time: 20 min
Cook time: 10 min
Total time: 30 min
Cuisine: American
Ingredients: 2¼ cups all-purpose flour*; 2 teaspoons baking powder; ¼ teaspoon kosher salt; ½ cup butter; 1 cup sugar; 1 egg; 1 teaspoon vanilla; 2 tablespoons lemon zest (finely minced, about 1 large lemon's worth); 1 tablespoon lemon juice; 2 cups powdered sugar; 2 tablespoons lemon juice; 1 cup brown rice flour *; ¾ cup oat flour *; ½ cup tapioca starch *; ¼ cup potato starch *; 1 teaspoon xanthan gum *