Sift together dry ingredients; cut in shortening until mixture resembles coarse crumbs. Combine egg and milk; add to flour mixture all at once. Stir until dough follows fork around bowl. Turn out on lightly floured surface; knead gently with heel of hand about 20 strokes. Roll dough to 3/4 inch thickness. Dip 2 inch biscuit cutter in flour; cut straight down through dough - no twisting. Place on ungreased baking sheet (3/4 inch apart for crusty biscuits, close together for soft sides). If desired, chill 1-3 hours. Bake in a very hot oven (450 degrees) 10-14 minutes or until golden brown. Cook sausage, crumbling well. Pour off all but 2-3 tablespoons of grease. Sprinkle flour on top. Increase heat to high and cook, stirring, until flour starts to brown. Add milk, stirring constantly and continue cooking until gravy thickens. Add salt and pepper. Serve over hot biscuits or toast.