Boil 2 1lb boxes of elbow maccaroni, drain then place in large casserole dish or aluminum serving pan.
Cut stick of butter into small to med sized pats then distribute equally into still hot pasta. Add onion powder, then mustard. Mix ingredients together.
In a seperate bowl mix together sour cream and 1/2 can evaporated milk until smooth and creamy.
Slowly begin adding shredded cheeses in layers, mixing into maccaroni after each layer. Save some sharp and extra sharp for top layer when done with preperation.
Pour sour cream mixture over the top, then remaining can of evaporated milk and stir until well mixed.
In a seperate bowl, beat the 5 eggs well and pour over top then 2 cups of milk mix well. Sprinkle remaining cheeses to cover top. Sprinkle paprika then black pepper over top of mixture.
Place in 375 degree oven on center rack, and bake for 1 hour. When done top layer should be golden brown and mixtue should be bubbly. Serve Immediately. Maccaroni and cheese should be creamy and gooey...NJOY !!!