In a small bowl, stir together flour, baking soda, and baking powder. Set aside.
In a large mixing bowl, cream together butter and sugar until smooth. Beat in the egg, lemon extract and juice. Gradually blend in dry ingredients.
Roll dough into 1-1/2" inch balls and place on an ungreased cookie sheet. Take a glass and dampen the bottom of it with water. Dip the bottom of a cup in a small bowl of granulated sugar, then slightly flatten the top of each cookie with the bottom of the glass.
Refrigerate the cookies for 30 minutes before baking.
Bake at 375 degrees for 7-8 minutes. To keep the cookies soft, they should not be browned. Allow the cookies to sit on the baking sheet for 3 minutes before removing them to a wire rack to cool completely.
In a small bowl, whisk the powdered sugar and lemon juice until smooth. Drizzle the glaze on the cooled cookies. Sprinkle with colored sprinkles, if desired.
Allow the glaze to set, then store the cookies in an airtight container.