8 slices of center cut bacon, cut into 1/4 inch thick pieces
2 tablespoons unbleached all purpose flour
2 cups warm whole milk
1 teaspoon salt
1/4 teaspoon ground dry mustard
1/4 teaspoon hot sauce
1/4 teaspoon Worcestershire sauce
1 1/2 cup shredded American cheese
1 1/2 cup shredded sharp Cheddar cheese
1 tablespoon minced fresh chives
8 cups hot cooked elbow macaroni (about 3 cups uncooked)
In a 10-inch cast iron skillet, cook the bacon over medium heat until crisp, about 5 to 6 minutes. Remove the bacon with a slotted spoon, and set aside. Reserve bacon fat in pan.
Cook pasta per manufacturer directions.
Whisk flour into the rendered fat. Cook whisking constantly, 2 minutes. Whisk in the milk, salt, mustard, hot sauce and Worcestershire. Bring to a simmer whisking constantly until thickened, almost 15 minutes.
Remove from heat. Add both cheeses and stir until melted and smooth. Stir in bacon, chives and cooked macaroni.