Preheat oven to 425 degrees F.
Spoon a dollop of vegetable shortening in skillet, and place in oven during preheating time.
Combine dry ingredients. Add egg, milk, oil and mayonnaise to dry ingredients, mix well. Remove pan from oven (be careful, it will be very hot) and pour batter into skillet. Bake at 425 degrees F for 20 to 25 minutes, or until golden brown.
Serves 8.