Bring 4 quarts water with 1 teaspoon salt to a boil in a large pot and cook pasta according to package directions. Strain and set aside.
Place a heavy saucepot over medium heat, add bacon to pot and allow it to render. Remove bacon bits and place on a plate lined with paper towels to drain. Set aside. Add shallots to pot and sauté for 2 minutes. Lower heat, add 4 ounces butter and melt completely. Using a wooden spoon, stir in the flour and continue stirring for 3 minutes. This will create a blond roux.
Slowly pour in milk while whisking vigorously. Continue whisking until the sauce comes to a boil. Reduce heat and allow it to simmer for 15 minutes. Add remaining salt and white pepper. Remove from heat and add remaining butter. Stir in cooked pasta and both cheeses.
Preheat oven to 350F. Transfer macaroni and cheese to a greased large baking dish or individual oven-proof serving dishes of your choice. Place in oven and bake 30 minutes.
Serve and garnish with bacon bits.
1 lb macaroni pasta
2 ½ tsp kosher salt, divided
4 slices good-quality uncooked smoked bacon, diced
5 oz butter, divided
¼ cup finely chopped shallots
½ cup all-purpose flour
5 cups whole milk, scalded
½ tsp ground white pepper
3 cups Gruyere cheese
1 cup Pecorino cheese
Serving Size: 4-6