2 cups sifted all-purpose flour
1/4 teaspoon salt
1/2 teaspoon baking powder
1/2 cup unsalted butter, softened
1 cup sugar
1 large egg
1 teaspoon vanilla extract OR 1 teaspoon fresh lemon juice and zest of 1 lemon
Royal Icing (recipe follows)
In a large bowl, sift together flour, salt, and baking powder. Set aside. In the bowl of an electric mixer, cream together butter and sugar until fluffy. Beat in egg. Add flour mixture and mix on low speed until thoroughly combined. Stir in vanilla or lemon juice and zest. Wrap dough in plastic; chill for 30 minutes.
Heat oven to 325 deg. On a well-floured board, roll out dough to 1/8 inch. Cut into desired shapes. Place on ungreased baking sheet and chill until firm, about 15 minutes. Bake for 8 to 10 minutes, or until edges start to brown lightly. Cool on wire racks.
Royal Icing
2 large egg whites
3-1/2 cups sifted confectioners' sugar
Juice of 1 lemon
2 drops glycerin
Food Coloring
Beat egg whites until stiff, but not dry. Add sugar, lemon juice, and glycerin. Beat 1 minute. If icing is too thick, add water. If too thin, add more sugar. Divide icing into smaller bowls. Tint with small amounts of paste or liquid food coloring if desired; mix well for an even color.