Preheat oven to 350 degrees F (180 degrees C).
In a skillet, cook the Bacon (6 slice). When crispy, drain on a paper towel lined plate and set aside. Reserve 4 tablespoon of the bacon grease. Cook the Penne Pasta (6 ounce) in salted water according to package's instructions. Reserve 2 tablespoons of pasta water.
In the same skillet, use the reserved bacon grease and sprinkle in Unbleached All-Purpose Flour (4 tablespoon) Whisk together for 3-5 minutes. The fat will absorb the flour to create a roux. Cooking will cook off the raw flour flavor.
When the roux turns sandy beige, pour in the Half and Half (4 cup). Whisk thoroughly to prevent any lumps.
Keep whisking and add Ground Nutmeg (1/2 teaspoon), Salt and Pepper (to taste) and Unsalted Butter (2 tablespoon).
Take the skillet off the heat and stir in the Cheese (1 pound), pasta water, and Egg (1).
Toss the cooked pasta in the cheese mixture.
In a buttered dish, layer in pasta with crumbled bacon. Reserve some of the crumbled bacon for topping.
Top with Panko Breadcrumbs (to taste) extra bacon and cheese.
Bake at 350 degrees F (180 degrees C) for 20-25 minutes. Cover with tin foil for half the baking time.
Broil for about 5 minutes to blister the cheese.