Preheat oven to 350°.

Place a large, covered pot of salted water over high heat. When the wa-ter boils, add the pasta, removing it a minute before you think it will be al dente. Drain the pasta and transfer it to an ovenproof bowl.

In a second, heavy-bottomed saucepan over medium-low heat, melt but-ter. over on medium-low heat. Whisk the flour. Cook the roux for 3 minutes, whisking all the while. When it is golden brown and has thor-oughly bubbled up across the surface of the pan, start adding milk, slow-ly, so you don’t shock the roux.

Keep whisking every minute or so to make sure the bottom doesn’t burn. The béchamel is done when it has thickened enough to coat a spoon. Season it with salt and pepper to taste. Add the cheese to the bowl and then the béchamel. Stir it all a few times. Tent loosely with foil and cook for 25 minutes, then increase the temperature to 375°, remove the foil, and cook for another 10 minutes or so until it gets golden brown on top.

Meanwhile, open the can of whole tomatoes and pour them into a small saucepan. Warm them gently until the mac and cheese is baked.

Serve pasta and tomatoes together in warm bowls.