Spicy Macaroni & Cheese

4 Cups Elbow Macaroni -- cooked until almost al dente
8 Ounces Cheddar Cheese -- 1/2 cubed, 1/2 grated
8 Ounces Colby Cheese -- cubed
8 Ounces Monterey Jack Cheese -- cubed
4 Teaspoons Flour
1 Teaspoon Salt
1 Teaspoon Freshly Ground Pepper
1 Teaspoon Cayenne Pepper
1 Teaspoon Dry Mustard
1/4 Teaspoon Ground Nutmeg
8 Tablespoons Sour Cream
2 Large Eggs -- beaten
2 Cups Heavy Cream
2 Cups Half-and-half
1/4 Cup Finely Grated Onions
Buttered Bread Crumbs

Preheat oven to 350°. Prepare a large 9 X 13" baking dish.

In a large bowl, toss together the pasta with the cheese cubes and pour into the baking dish.

In a large bowl, mix together the flour, salt, black pepper, cayenne pepper, dry mustard and nutmeg. Add the sour cream, eggs, heavy cream, half-and-half and onions. Pour over macaroni and cover with shredded cheddar cheese. Bake uncovered until the top is just beginning to brown, about 35 minutes. Add a layer of buttered bread crumbs and bake an additional 10 minutes.