- Sea salt and black or white pepper
- 2 small heads or 1 large head cauliflower (about 2 1/2 pounds), trimmed into florets and bite-size stems
- 3 tablespoons butter
- 1 large shallot, finely chopped
- 2 rounded tablespoons flour
- 1/2 cup dry white wine
- 1 1/2 cups whole milk
- Freshly grated nutmeg
- 1 tablespoon dijon mustard
- 1 cup shredded gruyere cheese (about 4 ounces)
- 1/2 pound french-style ham, prosciutto cotto or rosemary ham, cut into 1/4-inch pieces
- 1/2 cup grated parmigiano-reggiano cheese
- A generous handful flat-leaf parsley, finely chopped
Position a rack in the lower third of the oven and preheat to 500 degrees ; or preheat the broiler. In a large pot, bring a few inches of water to a boil, salt it, add the cauliflower and cook until crisp-tender, about 5 minutes. Drain and return to the pot.
Meanwhile, in a saucepan, melt the butter over medium heat. Add the shallot and cook for 3 minutes. Sprinkle in the flour and stir for 1 minute. Whisk in the wine, then the milk; heat through and season with sea salt, pepper and nutmeg to taste. Cook until thick enough to coat the back of a spoon, 2 to 3 minutes. Stir in the mustard and gruyere until melted, then remove from the heat.
Stir the ham and the gruyere sauce into the cauliflower, then transfer to a large, shallow casserole. Top with the parmigiano-reggiano and bake or broil until brown and bubbly, about 5 minutes. Remove from the oven and top with the parsley.