Preheat your oven to 325 degrees.

Grate your own cheese from a block, the pre-shredded stuff doesn’t melt as well.

Start a pot of 4 quarts water to boiling with 1-2 Tbsp of salt.

Pour the milk and let it sit out to come to room temperature.

Cook the macaroni or rotini to al dente

Start frying the bacon in a large skillet, we want it done but not crisp.

While the pasta is cooking and the bacon is frying, mince the onion

Remove the bacon when done & sauté the onion in the grease until soft.

Chop the bacon up into bacon bit pieces.

When the pasta is finished, drain, rinse, and pour into a large mixing bowl.

Add the butter to the skillet to melt, and then add the flour.

Stir constantly until the flour takes on a tan color.

Whisk the milk into the roux, adding a little bit at a time.

Bring it back to a simmer and cook, stirring constantly, until thickened.

Reduce to low heat, add the seasoning and the mustard.

Stir in 80-90% of the shredded cheese, a little at a time, and stir until melted.

Add the bacon back to the cheese sauce and stir through.

Add the cheese sauce to the pasta and mix well.

Put the mac and cheese into your casserole dish(s).

Top with the remaining cheese and the bread crumbs.

Bake for 30-40 minutes, until the top is golden brown.