Cook the bacon and set aside to cool.

Cook the macaroni to al dente. You want it to be slightly under done since it will cook a bit more in the oven.

In a large pot, melt the butter over medium heat and then whisk in the flour. Cook for 3 minutes, stirring constantly.

Add in the milk and mustard, stir good. Cook until the sauce has thickened up quite a bit, about 5 minutes and then reduce heat to low.

Take a few tablespoons of the sauce and pour into the egg while whisking. Let that cool a bit and then add it into the pan with the sauce. Stir.

Add in a cup and a half of the cheese (saving the rest for topping) and continue to stir until all of the cheese is completely melted.

Before adding S&P (or any extra spices) taste the cheese sauce to see how you would like it. It may be salty enough for your liking and you'll only want a bit of pepper. S&P to taste.

Pour cooked macaroni into the cheese sauce, stir, and then pour into a casserole dish.

Chop bacon, stir into the macaroni and cheese, and then spread the mixture evenly out among the dish.

Top with cheese and bake at 350 degrees F for 25 minutes.

ENJOY!