Funny, now that zucchini is actually in season, this dish is no longer on the menu at Prune. No worries though, since we can all make it in the comfort of our own kitchen now.
2 tablespoons butter
1 tablespoon/10 grams flour
24 ounces zucchini (about 6 medium ones), trimmed and cut into 1/2-inch coins
1 1/4 cups/312 ml millk
Sea salt and freshly ground black pepper, to taste
Generous pinch of freshly grated nutmeg
Melt the butter in a heavy-bottomed 2-quart pot over medium heat. Add the flour, and cooking stirring with a wooden spoon until the mixture starts to foam and turns golden. Stir in the zucchini, making sure all the pieces are well-coated. Stir in the milk, and add the salt, pepper and nutmeg.
Bring to a boil, then reduce heat to lowest setting and cover pot with a lid. Cook for 25 to 30 minutes, until the zucchini is extremely tender when pierced with the tip of a fork. Don't worry if the sauce looks curdled or broken—just stir it together a few times and will come together into a velvety texture. Let the zucchini sit in the pot, uncovered, for 5 to 10 minutes so the sauce can thicken further, before serving.