Cook macaroni according to package instructions. Drain; rinse.
In a saucepan, melt butter, remove from heat, add flour, salt and pepper and mix well. Put back on low heat and gradually add milk. Stir well til milk is warmed. Add cubed Velveeta cheese. Stir frequently til melted. Reduce heat, cover for about 15 minutes. If cheese sauce seems too thick, add a little more milk. You want a real creamy consistancy.
In a deep casserole dish put cooked macaroni and cheese sauce. Blend so that all macaroni is coated in cheese sauce. Sprinkle with shredded cheese. Bake in 400F degree oven til cheese is bubbly and slightly browned.