Cook macaroni according to package instructions. Drain and set aside.
In a large saucepan, melt butter over medium heat. Stir in flour until smooth.
Gradually whisk in milk and cream. Bring to a gentle boil, stirring constantly.
Reduce heat and stir in cheddar, mozzarella, Parmesan, salt, and pepper. Cook until cheese melts.
Add cooked macaroni to the sauce and mix well.
Pour mixture into a greased 2-qt baking dish. Sprinkle bread crumbs on top if desired.
Bake at 375°F for 20-25 minutes, or until bubbly and golden.