For Gingerbread Cookies:
Preheat oven to 350 degrees F.
In a large mixing bowl, blend all ingredients together and chill for up to 1 hour. Roll dough out on floured board about 1/8-inch thick. Cut desired shapes with cookie cutters and place onto sheet pan. Bake for 8 minutes in preheated oven.
For Royal Icing:
With a hand mixer, beat the egg whites with the lemon juice or extract until frothy. Add the sifted powdered sugar and beat on low speed until combined, smooth, and shiny. Turn to high and beat approximately 5 minutes till stiff and glossy. Add food coloring, if desired, and transfer to a pasty bag to pipe onto cookies.