Mix shortening, sugar, eggs and lemon extract well. Sift together flour, baking powder and salt, and stir in wet ingredients until combined. Chill for 1 hour.
Once dough has been chilled, preheat oven to 400 F and prepare paint. Mix 1 egg yolk with 1/4 teaspoon water. Divide into two small cups and add desired food coloring to each.
Roll out 1/4 of the dough at a time to 1/8-inch thick while keeping remaining dough chilled. Cut in desired shapes. Place on an ungreased baking sheet and paint with egg yolk paint.