Directions
1. Bring a large pot of salted water to a boil. Boil the macaroni according to package directions, draining when it is just becoming al dente. This will bake more in the oven, so don’t overcook it. Drain and toss with 2 tablespoons butter.
2. If the bread isn’t fully dried, toast it on a tray in the toaster oven, toaster or skillet, and then allow to cool. Grind in a food processor until you have fairly coarse crumbs. Heat 2 tablespoons butter in a skillet over medium heat, add the garlic, a pinch of salt, and the breadcrumbs. Cook, tossing frequently, until lightly browned. Set aside to cool. At this point people will be crowding your kitchen, asking “what’s for dinner?” because of the smell of garlic butter.
3. Preheat oven to 350 and grease a large baking dish.
4. In a medium saucepan, melt the remaining 4 tablespoons of butter over medium-low heat. Sprinkle in the flour and whisk pretty constantly for 3 minutes. Whisk in the milk. Add the onion, smoked paprika, rosemary, chipotle, oregano, and nutmeg. Simmer, whisking occasionally until it begins to thicken.
5. Gradually whisk in the grated cheeses, stirring each batch to incorporate.
6. Taste the sauce, and adjust the seasoning to your preference. It will probably need a little salt, but maybe not too much depending on the cheeses. Add more spiciness if desired. Remember that the sauce should be pretty intense because it is going to be diluted by a full pound of pasta.
7. Stir the macaroni into the sauce. Pour the macaroni into the prepared pan.
8. Top with the garlicky breadcrumbs (you might not need all of them).
9. Bake for about 30 minutes, until you can see bubbling around the sides and the breadcrumbs are nicely browned.
10. Let stand for 5-10 minutes (to set) and serve.