Boil pasta in salted water, according to packet instructions, until JUST al dente (do not over-boil)! Drain and rinse well with cold water. Set aside.
Preheat oven grill or broiler to 190°C | 375°F.
FOR CRISPY TOPPING:
Melt 2 tablespoons butter in a large, oven proof pan or skillet over medium-high heat. Add in the Panko breadcrumbs; stir to coat and cook until golden browned. Transfer to a bowl; set aside.
FOR THE SAUCE:
Melt the 1/4 cup of butter in the same pan / skillet. Add the garlic and sauté until just fragrant (about 1 minute). Whisk in the flour; continue to cook while whisking (or stirring) for at least 2 minutes. Reduce heat down to low; gradually whisk in 4 cups of the milk (about 1/4 cup at a time), whisking between each addition to combine. Bring to a boil until beginning to thicken.
In a separate jug, combine the cornstarch and remaining 1/2 cup milk; whisk until lump free and stir through the white sauce to thicken completely. Season with salt and pepper and stir in the bouillon powder.
Remove from heat and add in the cheddar, 3/4 cup of parmesan cheese, and the mozzarella slices. Stir through until all of the cheese has melted. Toss the pasta through the sauce until completely coated.
Top with the Panko and the remaining parmesan cheese. Broil (or grill) in oven for about 10-15 minutes, or until bubbling.
Allow to cool down slightly before serving.
Video
Notes
Storage, Reheating, and Make Ahead
Storage: For proper storage, let the mac and cheese cool completely before transferring your leftovers into an airtight container. Store it in the fridge for up to 4 days, or freeze in a sealed freezer-safe container for up to 2 months.
Reheating: Reheat over medium-low heat on the stove. The pasta absorbs the sauce as it sits, so stir in a splash of whole milk or chicken broth as it warms to bring back that creamy texture. You can also microwave individual portions in 30-second bursts.
Make Ahead: You can assemble the entire dish in your baking dish (without baking), cover tightly with foil, and store in the fridge overnight. When you are ready to serve, bring it to room temperature for 20 minutes, pop on the topping, and bake as directed.
Happy cooking! Xx
Grate your own cheese from a block! Pre-shredded packaged cheeses contain anti-caking agents that stop them from melting properly, leaving you with a grainy sauce instead of a silky smooth one.