Preheat oven to 350F.
Liberally butter the bottom and sides of a large springform pan.
After the pan is buttered lightly sprinkle with cheddar cheese. Set aside.
Boil macaroni in salted water 2 minutes before al dente. We don't want the pasta to be fully cooked as it will be absorbing the cheese sauce in the oven.
Strain macaroni and add to a large mixing bowl.
Meanwhile in a large saucepan over medium heat melt butter. Add flour and stir to create a thick roux for 3-5 minutes.
Season with salt, pepper and nutmeg.
Add Dijon mustard and Worcestershire sauce.
Slowly add warm milk and stir with a whisk until the roux thins out into a creamy bechamel sauce.
Turn the stove down to medium-low heat and stir for 20 minutes until all of the milk has been incorporated. It is so important to stand over the stove and watch carefully. If you don't, your flour will form clumps and ruin the consistency of your sauce.
Slowly add shredded cheeses to the bubbling sauce, stirring to incorporate.
Once the cheese sauce is perfectly smooth pour over macaroni. I like to make so much sauce that it looks like a borderline soup. The pasta will quickly absorb the sauce in the oven so be sure to toss so all of the noodles are incorporated.
Use a large spoon to layer the pulled pork mac and cheese in the springform pan. Alternate by adding shredded cheese, macaroni cheese mixture and pulled pork.
Finish the casserole by sprinkling the top with bread crumbs.
Place the springform pan on a baking sheet and bake in a 350F pre-heated oven for 45 minutes.