Homemade Genoa mac and cheese is better — by far — than any frozen or boxed version. Does anyone want to argue that? No? That’s because you’d lose. Ours is super creamy, using a blend of mild and sharp cheese, with a welcome surprise of salami bits in each bite. Pure comfort. Plus a crunchy topping. Could you want anything more? You’ll never go back to the box.
Butter a 9-by-13-inch baking dish. Bring a large pot of well-salted water to a boil. Add the pasta and cook until tender, according to box directions. Drain.
Meanwhile, melt the 5 tablespoons of butter in a large saucepan over medium heat. Mix the flour, dry mustard, paprika, cayenne, and 1 teaspoon salt in a small bowl. Add a little of the dry mixture at a time to the butter, whisking, until it’s a smooth paste. Cook, whisking until the raw flour smells go away and the paste smells a little nutty, about 2 minutes. Slowly whisk in the milk. Let the sauce come to just a boil, and then continue to cook, whisking, until the sauce thickens, about 5 more minutes. Turn off the heat and add the cheeses in handfuls, whisking to make a smooth sauce.
Preheat the broiler.
Stir in the cooked pasta and Genoa cubes until well combined. Scrape into the prepared baking dish. Mix the panko, Parmigiano or asiago, and oil together, scrunching with your hands to incorporate. Sprinkle evenly over the pasta. Broil until the topping browns nicely, 3 to 4 minutes.