Cook macaroni according to package directions in boiling salted water; drain and set aside.

Combine milk, 3 tablespoons melted butter, fluor, salt, pepper, and eggs in a mixing bowl; whisk until smooth and well-blended. Layer half of cooked macaroni in bottom of a shallow, buttered 2 quarter baking dish; sprinkle with 2 cups cheese and top with remaining macaroni.

Pour milk and egg mixture over macaroni. Toss breadcrumbs with remaining 1 tablespoon melted butter; sprinkle bread crumbs over the top of macaroni and cheese mixture. Bake macaroni and cheese at 350, uncovered, for about 45 to 50 minutes; sprinkle with remaining cheese and continue baking for about 5 minutes longer, or until macaroni and cheese is set.