1/2 cup vegetable shortening
1 cup milk
1 1/2 teaspoons vanilla extract
2 cups plus 2 tablespoons all-purpose flour
1 1/2 cups granulated sugar
4 teaspoons baking powder
1 teaspoon salt
4 large egg whites
1/2 cup powdered sugar
Heat the oven to 350 F, and grease and flour a 10-inch cast-iron skillet or baking dish.
In a large mixing bowl, cream together the shortening and milk, beating it for about three minutes. Add the vanilla and mix it in.
In a medium bowl, whisk together the flour, sugar, baking powder and salt.
Add the dry ingredients, one-third at a time, mixing between additions, until smooth.
Add the egg whites and mix just to incorporate them.
Transfer the batter to the prepared skillet, and bake for 40 to 45 minutes, until a toothpick inserted in the center comes out clean.
Remove it from the oven, and let cool in the skillet on a wire rack for at least an hour before dusting with powdered sugar, slicing into wedges and serving.