The Food Lab's Creamed Spinach

Ingredients

• 3 tablespoons unsalted butter
• 2 medium shallots, finely minced
• 2 medium cloves garlic, minced or grated on a Microplane
• 2 pounds curly spinach, trimmed, washed, and drained
• 1 tablespoon all-purpose flour
• 1 1/2 cups heavy cream
• 1/2 cup whole milk
• 1/4 teaspoon freshly grated nutmeg
• 1/4 cup store-bought or homemade crème fraîche
• Kosher salt and freshly ground black pepper
• 2 ounces Parmigiano-Reggiano, finely grated

Directions

1. Warm the butter in a Dutch oven or large saucepan set over medium-high heat. Stir in the shallots and garlic, and cook until they soften, about 2 minutes. Add the spinach in 4 batches, using tongs or a rubber spatula to turn each addition until it wilts enough to make room for the next.
2. Sprinkle in the flour and stir nonstop until you no longer see any dry bits. Gradually add the heavy cream and milk, stirring as you pour. Bring the mixture to a simmer, then turn the heat down as low as it will go and continue cooking, stirring now and then, until the spinach is fully tender and the sauce has thickened, about 1 1/2 hours.
3. Mix in the nutmeg and crème fraîche, then season with salt and pepper to taste. Take the pan off the heat.
4. If you want the cheesy top, heat the broiler to high. Spoon the creamed spinach into a 1-quart oval or round casserole dish, then scatter the cheese over it. Broil until the spinach is bubbling and the cheese turns into a deeply browned crust, about 2 minutes. Serve.