Creamed spinach was one of those special occasion side dishes my mom served us as kids. Although she usually worked with frozen spinach, which is fine, it's even better using fresh spinach. The richest and most luxurious way to make this recipe is with - surprise! - heavy cream. But because I like a lot of creamed spinach, and I don't like a lot of heavy cream, I prefer to make it using a bechamel sauce, which is milk thickened with a butter/flour mixture. I have prescribed whole milk for my bechamel, but you could get away with 2 percent or even 1 percent milk. The crispy shallots provide a great contrasting garnish to the creamed spinach, but if you don't have the time or inclination to add them, the spinach is great all by itself.
To prepare the shallots: Fill a deep saucepan with about 2 inches of vegetable oil. Heat over medium heat until a deep-fat thermometer reads 360 degrees. (Alternatively, use an electric deep-fat fryer). Toss the shallots with the flour in a large bowl, to coat. Transfer to a strainer and shake to remove the excess flour. Add the shallots to the hot oil and cook until golden brown, about 2 minutes. Remove the shallots with a slotted spoon, drain on paper towels, and sprinkle with salt and pepper.
Wash the spinach in several changes of cold water. Drain in a colander and pile into a large non-reactive pot. Place the pot over medium heat and cook, stirring, until just wilted, about 3 minutes. (The spinach will steam and cook in the water clinging to its leaves.) Drain and rinse under cold running water. Use your hands to squeeze out the water. Transfer to a work surface and coarsely chop. Melt the butter in a small saucepan over medium heat. Add the flour and cook, stirring, for 2 minutes. Pour in the milk, whisking constantly, and increase the heat to medium-high. Bring to a simmer, stirring often, and cook until thick and smooth, 3 to 5 minutes. Season with nutmeg, salt, and pepper. Stir in the spinach just before serving and warm through under low heat, about 3 minutes.
Serve the spinach hot, garnished with the fried shallots.
When I was making creamed spinach on the show, a fellow named John from Brooklyn called in to tell me his favorite way to squeeze water out of blanched spinach: in a potato ricer! I tried it, and he is right.