Although there is no question that fresh spinach is better here, you may make your life easier and use frozen. There, I’ve said it. Just don’t quote me.
This colorful treat is an excellent first course for diner. Throw a bit of smoked salmon or prosciutto on top, and you have an unusual main dish for lunch that is lighter, for those of us who worry about these things, than the splurge of a cheese soufflé, but that is certainly no less appetizing.
YIELD: 4 to 6 servings
5 tablespoons salted butter, plus more for the soufflé dish, divided
6 tablespoons Parmesan cheese
2 pounds spinach
1 ½ teaspoons salt, plus a pinch, divided
¼ teaspoon black pepper
1 cup half-and-half
½ teaspoon white pepper
1 teaspoon minced garlic
½ teaspoon nutmeg
3 tablespoons flour
6 egg yolks
1 cup grated Gruyère cheese, firmly packed
1 tablespoon Dijon mustard
2 teaspoons dry vermouth
8 egg whites
Preheat the oven to 400°F. Butter a 6-cup soufflé dish, or two 4-cup soufflé dishes. The smaller the dish, the higher the soufflé will rise. Add 2 tablespoons of the Parmesan cheese and shake the buttered dish to coat it with the Parmesan.
In a large heavy skillet over a medium-high heat, melt 2 tablespoons of the butter. Add the spinach, ½ teaspoon of the salt, and the black pepper.
Cook the spinach until it is wilted and then remove it from the heat and drain it in a colander.
Using a kitchen cloth or a paper towel, squeeze the excess liquid from the spinach. Don’t be surprised at how much liquid will be removed, and get it all out!
Chop the spinach and reserve it.
In a medium stockpot over medium-high heat, heat the half-and-half, 1 teaspoon of the salt, the white pepper, garlic, and nutmeg, until they are scalding but not boiling.
In a small skillet over a medium heat, melt the butter and add the flour to make a roux. Add the roux to the half-and-half and whisk it vigorously to fully combine so there are no lumpy bits of roux in the milk. Bring the mixture to a boil and then remove it from the heat. It will have thickened considerably.
Let the mixture cool for 5 to 10 minutes and pour it into a medium mixing bowl.
Stir in the egg yolks, one by one, and then the remaining 4 tablespoons of Parmesan cheese, the Gruyère, mustard, and vermouth to combine with the egg mixture.
In the bowl of a large electric stand mixer fitted with the whisk attachment, beat the egg whites with a pinch of salt until they stand in soft peaks. Add 1/3 of the whipped egg whites to the mixing bowl and stir it well to lighten the mixture. Fold in the remaining egg whites.
Reduce the oven temperature to 350°F.
Pour the soufflé mixture gently into the prepared soufflé dish so as not to deflate the egg whites, and bake it for 25 to 30 minutes until it has risen. Serve it immediately.