Preheat the oven to 300 degrees F.
Melt the butter in a sauté pan; add the oregano, hot sauce, salt, pepper, and breadcrumbs. Toss to coat. Spread the mixture onto a sheet pan and toast in the oven until golden brown, 10 to 15 minutes. Reserve and cool to room temperature.
Preheat the oven to 400 degrees F.
In a large pot, bring the water and salt to a boil. Add the pasta and cook until al dente, about 10 minutes. Drain the pasta and cool in the refrigerator on a cold sheet pan.
In a separate pot, melt the butter. Whisk in the flour and continue stirring for about 5 minutes. Be sure the mixture is free of lumps and then add the milk, onion, bay leaves, mustard, and paprika. Stir and simmer for 5 minutes; remove the bay leaves.
In batches, add the cheeses, being careful not to break the sauce. Season with salt and pepper. Fold the macaroni into the cheese mixture. Add the hot sauce and stir well. Pour the mixture into a large, deep casserole dish and top with the remaining cup of cheese. Sprinkle with the prepared breadcrumbs. Bake until bubbly, 25 minutes.