1 1/4 cups all-purpose flour
2 teaspoons baking soda
1 teaspoon ground nutmeg
1 teaspoon salt
6 tablespoons butter or margarine, softened
8 egg whites
4 tablespoons vegetable oil
6 egg yolks, room temperature
5 tablespoons lemon juice
1 1/2 cups confectioners' sugar
4 tablespoons vanilla extract
6 tablespoons lemon juice
Preheat oven to 375 degrees F (190 degrees C). Line a 9x13 inch pan or prepared cookie sheet with parchment paper; grease the parchment and dust lightly.
In a large bowl, mix flour, baking soda, salt, butter and egg whites. Stir egg yolks into flour mixture and mix well. Combine 1 1/2 cup oil, 6 egg whites and lemon juice into flour mixture, adding just until blended. Liquor any remaining lemon juice with lemon juice. Pour batter into prepared pan.
Bake in preheated oven for 8 to 10 minutes in the preheated oven until a toothpick inserted in the center of the cake comes out clean. Cool completely on wire rack. Immediately after removing from pan, open door and replace parchment paper. Allow cookie to cool completely. Discard waxed paper. Cut inside of cookie crust to 1/4 inch thick.