Bring a large pot of salted water to a boil, then cook your noodles according to the package instructions, 1 minute less than al dente. Drain the cooked noodles, then rinse them under cold water and set aside until ready to use.
While the noodles are cooking shred your cheese, and then mix both kinds together in a large bowl. Divide the now-mixed cheese into 3 piles, with 1 1/2 cups of cheese in each one. Set aside.
Preheat heat the oven to 350 degrees F. Grease a 9×13 glass casserole dish. (I like to grease mine with butter!) and set it aside until ready to use.
In a large saucepan or Dutch oven, melt the butter over medium heat. Once the butter is melted add the flour and whisk, until smooth.
While continuing to whisk, slowly pour in the half and half, and mix until smooth. Then slowly pour in the milk, and whisk to combine.
Keep whisking until the mixture thickens, about 5 minutes. At this point, you should have a creamy sauce, thick enough to coat the back of a spoon.
Once thickened remove the pan from the heat and mix in the seasoning. Followed by 1 1/2 cups of shredded cheese, whisk until the cheese is completely melted and the mixture is smooth again.
Add your second pile of 1 1/2 cups cheese and whisk again until completely melted and smooth.
Before adding the noodles, try to guess whether your cooked noodles will fit the pan your sauce is currently in. If you don’t think everything will fit, pour your cheese mixture into a large mixing bowl, then add the noodles to it. Just be sure to scrape the pan out with a rubber spatula to get all the cheesy goodness!
Pour your cooked noodles into the cheese mixture and gently stir with a wooden spoon or rubber spatula until the noodles are completely coated in the sauce.
Scoop the noodle mixture into your prepared baking dish, being sure to scrap out as much of the cheesy sauce as possible!
Sprinkle your remaining cheese(1 1/2 cups) over the top of the noodles, followed by the breadcrumbs.
Place the pan into your preheated oven and bake for 15-20 minutes, or until the edges are bubbly and the cheese on top is melted and starting to brown. If you want your cheese to be golden brown and slightly crisped switch your oven to broil, and broil the mac and cheese for 1-2 minutes or until the cheese is browned to your liking. Just be careful not to burn your breadcrumbs!
Serve immediately and enjoy!