1 pound fresh spinach, tough stems discarded3/4 cups heavy cream or whole milk, or a mix thereof 1/2 small onion, finely chopped 1 small clove garlic, minced (optional) 2 tablespoons unsalted butter 3 1/2 teaspoons all-purpose flour Pinch of freshly grated nutmeg
Wash your spinach well but no need to spin or pat it dry. Place spinach in a large pot over high heat. Cook, covered, with just the water clinging to leaves, stirring occasionally, until wilted, about 4 to 6 minutes.
Press or squeeze out the excess liquid any number of ways, either by wringing it out in cheesecloth, putting it in a mesh strainer and pressing the moisture out with a spatula or large spoon or letting it cool long enough to grab small handfuls and squeezing them to remove as much water as possible. Coarsely chop the wrung-out spinach. Wipe out large pot so you can use it again.
Heat milk or cream in a small saucepan over moderate heat, stirring, until warm. Keep warm. Meanwhile, cook onion and garlic, if using, in butter in your wiped-out large pot over moderately low heat, stirring occasionally, until softened, about 6 minutes. Whisk in flour and cook roux, whisking, about 3 minutes. Add warm milk or cream in a slow stream, whisking constantly to prevent lumps, and simmer, whisking, until thickened, 3-4 minutes. Stir in nutmeg, spinach, and salt and pepper to taste and cook, stirring, until heated through.
adapted from smittenkitchen.com