Preheat oven to 350ºF. Butter a 7 x 10″ baking dish. Place baking dish on a parchment-lined baking sheet.

Bring a large stock pot of water to boil. Salt water and boil pasta for 7 minutes. Drain, add 1 tablespoon butter and set aside.

Place bacon in a cast iron skillet and cook until slightly crispy. Drain on paper towels. When cool enough to touch, rough chop and set aside.

Cut bread of your choice into 1-inch cubes. Toss cubes into a small mini food processor and grind to fine crumbs. Place on a small baking sheet and toast in the oven for 7 minutes. Set aside.

Combine whole milk and heavy cream in a small, heavy duty saucepan and warm over medium heat (don’t boil). Add 2 tablespoons of butter, Celtic sea salt, white pepper, and nutmeg. When warm to the touch, add 1 1/4 cup of cheddar and the fontina to the milk mixture. Whisk until melted.

In the same pot that you boiled the water in, combine the pasta, cheese-milk mixture, and the bacon. Pour into prepared baking dish.

Top with the remaining 1/4 cup white cheddar. Sprinkle with bread crumbs and Parmesan cheese. Dot with the remaining 2 tablespoons of butter.

Bake for 20-30 minutes or until slightly golden on top and bubbling. Let sit for 5 minutes before devouring.