Lightened-Up Mac and Cheese

Directions

1. 1
   Bring a pot of salted water to a boil.
2. 2
   Add the pasta and cook as the label directs.
3. 3
   Reserve 3/4 cup of the cooking water, then drain the pasta.
4. 4
   Add the butter to the empty pot and melt over medium-high heat.
5. 5
   Add the shallot and cook, stirring, until slightly softened, about 2 minutes.
6. 6
   Add the flour and mustard powder and cook, stirring, until the flour begins to toast, about 1 minute.
7. 7
   Whisk in the milk and the reserved cooking water; cook, whisking, until thick, about 2 minutes.
8. 8
   Reduce the heat to medium.
9. 9
   Whisk in the sour cream, mozzarella, Swiss cheese and 1 tablespoon parmesan; continue whisking until melted, about 1 minute.
10. 10
    Stir in the pasta, 1/2 teaspoon salt and 1/4 teaspoon pepper; transfer to a 2-quart baking dish.
11. 11
    Preheat the broiler.
12. 12
    Combine the remaining 2 tablespoons parmesan, the herbs, and salt and pepper to taste in a small bowl.
13. 13
    Sprinkle over the pasta.
14. 14
    Broil until golden and bubbly, about 2 minutes.
15. 15
    Photograph by Antonis Achilleos