Preheat oven to 350 degrees. In a large bowl, cream together butter and sugar, until light and fluffy, about 4 minutes.
Add egg, egg yolk, lemon zest, lemon juice, and lemon extract. Mix for 1 minute longer.
Fold in flour, baking powder, and salt. Add yellow food coloring, if so desired. Chill the cookie dough for 15-30 minutes.
Place powdered sugar into a bowl. Roll the cookie dough into small balls and then roll into the powdered sugar, coating it well.
Place on a light-colored parchment-paper lined baking sheet. Bake for 9-11 minutes, until the cookies are still soft in the center. Remove from the oven and let cool on baking sheet for 5-10 minutes.
