1. Prepare the Pasta and Preheat the Oven

Start by cooking the pasta in a large pot of well salted boiling water until just shy of al dente, because it will continue cooking in the oven and in the cheese sauce. Drain it well and set it aside in a large bowl or pot so it is ready to be coated in the sauce later, making sure there is no excess water clinging to the pasta.​

While the pasta cooks, preheat the oven to around 400 degrees Fahrenheit so it is fully heated by the time you finish assembling the dish, which helps the topping become deeply golden and crisp in a relatively short bake. Lightly butter or spray a baking dish that will comfortably hold the pasta and sauce, so the finished mac and cheese unmolds neatly and does not stick.​

2. Brown the Spanish Chorizo

Place a medium skillet over medium high heat and add the diced Spanish chorizo in a single layer, allowing the fat to render and the edges to turn slightly crispy and caramelized. Stir occasionally so the chorizo cooks evenly and does not scorch, and keep the heat steady so the pieces sizzle and brown rather than steam.​​

Once the chorizo is nicely browned and has released a good amount of its flavorful oil, remove it with a slotted spoon and transfer it to a plate lined with paper towel to blot any excess grease, reserving a small amount of the rendered fat if you like a bit of its flavor in the sauce. This step concentrates the chorizo flavor and prevents the final dish from feeling greasy while still giving each bite a smoky, savory punch.​

3. Build the Roux for the Cheese Sauce

In a large saucepan or deep skillet, melt 4 tablespoons of unsalted butter over medium heat until fully melted and just starting to foam, but not browned. Sprinkle in the 4 tablespoons of flour and whisk continuously, cooking the mixture for a couple of minutes until it forms a smooth paste and loses its raw flour taste while still remaining pale.​

As the roux cooks, keep the whisk moving around the pan to avoid clumps and to prevent any scorching on the bottom, aiming for a silky, glossy paste that will thicken the milk evenly. This patient whisking is essential because a well cooked roux gives the cheese sauce body and smoothness without any chalky flavor.

4. Add the Warm Milk and Season the Base

With the heat still on medium, begin adding the warmed whole milk a little at a time, whisking vigorously after each addition to incorporate it fully into the roux and avoid lumps. Continue adding the milk gradually until all 2 cups are used and keep whisking until the mixture is completely smooth and begins to gently bubble.​

Once the sauce base has thickened to a consistency that lightly coats the back of a spoon, season it with a pinch of nutmeg, a small amount of salt, and freshly ground black pepper, remembering that the cheeses and chorizo will add more saltiness. Adjust the heat as needed to maintain a gentle simmer rather than a rapid boil, which helps the sauce thicken and develop flavor without separating.​

5. Melt in the Cheeses

Lower the heat to medium low and add the shredded Monterey Jack cheese to the hot béchamel in small handfuls, stirring between each addition so it melts evenly into the sauce. When most of the Monterey Jack has melted and the sauce looks smooth, add the grated Parmigiano Reggiano and continue stirring until the sauce becomes glossy and slightly stretchy.​

If the sauce seems too thick at this point, splash in a little extra warm milk to loosen it, aiming for a texture that is pourable but still rich enough to cling to each piece of pasta. Taste and adjust for salt and pepper once more, because the seasoning should be balanced at this stage before it coats the pasta and meets the chorizo.

6. Combine Pasta, Chorizo, and Cheese Sauce

Pour the hot cheese sauce over the cooked pasta in its large pot or mixing bowl and toss thoroughly so every curve and surface of the corkscrew pasta is generously coated. Take your time folding the sauce into the pasta rather than stirring aggressively, which helps avoid breaking the pasta and ensures the sauce stays thick and creamy.​​

Add the browned chorizo to the sauced pasta and gently fold it through, distributing the pieces so there is a bit of chorizo in every serving, without overmixing to the point where the chorizo starts to crumble too finely. As you stir, the chorizo’s smoky oil will lightly streak the sauce with color, creating a beautiful marbled effect and infusing extra flavor into the mac and cheese.

7. Prepare the Spiced Breadcrumb Topping

In a small saucepan or skillet, melt the remaining 2 tablespoons of butter over low to medium heat and then remove the pan from the heat so the butter does not brown. Stir in the breadcrumbs until they are evenly moistened and begin to absorb the butter, forming a loose, sandy mixture.

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Season the buttery crumbs with granulated onion, granulated garlic, and paprika, tossing until the spices are evenly distributed so every spoonful of topping carries flavor and gentle warmth. Taste a tiny pinch if you like, and adjust the seasoning slightly with salt or pepper if needed, keeping in mind that the topping should enhance rather than overpower the cheese sauce beneath it.​

8. Assemble and Bake the Mac and Cheese

Transfer the cheesy pasta and chorizo mixture into the prepared baking dish, smoothing the top with a spatula so it sits in an even layer without compacting it too firmly. Sprinkle the seasoned breadcrumb mixture evenly over the surface, covering the pasta completely for a uniform golden crust as it bakes.​

Place the dish in the preheated 400 degree Fahrenheit oven and bake until the top is deeply golden and crisp and the edges are bubbling, typically around 20 minutes, depending on your oven and the depth of the dish. Let the mac and cheese rest for a few minutes out of the oven before serving so the sauce can settle slightly, which helps you scoop neat, rich portions that hold together.​