01 -
Preheat the oven to 425°F (218°C). Shred all cheeses and set aside 1 cup each of medium cheddar, Colby Jack, and mozzarella for the topping. Grease a 9x13-inch casserole dish.
02 -
Bring a large pot of salted water to a boil. Add elbow macaroni and cook just under al dente, about 1-2 minutes less than package directions. Reserve 1 cup pasta water, then drain the pasta and set aside.
03 -
In a large skillet, melt 5 tablespoons butter over medium-high heat. Add minced garlic and sauté until fragrant, about 1 minute. Whisk in flour and cook, stirring, for 2-3 minutes until lightly golden.
04 -
Slowly whisk in reserved pasta water, heavy cream, and half-and-half until smooth. Reduce heat to low. Add medium cheddar, Colby Jack, mozzarella, sharp cheddar, and white cheddar cheeses one handful at a time, whisking until completely melted after each addition. Stir in cream cheese, mustard powder, paprika, onion powder, salt, and pepper until the sauce is silky.
05 -
Add cooked macaroni to the prepared casserole dish. Toss with 2 tablespoons melted butter until coated evenly.
06 -
Pour the cheese sauce over the macaroni. Fold gently until pasta is thoroughly coated with the sauce.
07 -
Sprinkle the reserved medium cheddar, Colby Jack, and mozzarella cheeses evenly over the top.
08 -
Bake in the preheated oven for 10 minutes until bubbling at the edges. Switch the oven to broil and broil for 5 minutes, monitoring closely, until the top is golden and crisp.
09 -
Remove from oven and allow to rest for 5 minutes before slicing. Serve warm for the creamiest texture.