Cut all slices of bacon in small pieces. It is easiest to do this when they are very cold, maybe even slightly frozen. Cook bacon in a pan until almost done.
Take out ¼ to ½ of bacon and set aside. Cook remaining bacon until crisp and set aside. Keep bacon fat in pan.
At this point you can cook your pasta separately according to package instructions.
Put a couple tablespoons of flour into pan and stir with bacon grease until lumped and slightly brown to make a roux.
Stir in warm milk to make a béchamel sauce. When sauce is thick and creamy, add your cheese, but save some to the side. If sauce is too thick, add some more milk. If sauce is too thin, add some more cheese. Don’t forget to season and taste!
Now add your cooked pasta and completely cooked crisp bacon. Mix together.
Pour some of mixture into an oven pan. Layer more of cheese. Add more mixture, then layer more cheese.
Use a food processor to chop up some stale bread, or crackers, or what have you with any herbs you desire. Mix with Parmesan cheese and sprinkle on top of mac n cheese. Add your almost cooked bacon on top of the topping.
Place in oven at about 350 degrees for 15-20 minutes. Put on broil for another 5-10 minutes to brown top.