A hearty pasta packed with vegetables, this supper is finished in 20 minutes flat. Sautéed leaks and shrimp combined with a touch of cream, lemon zest, and a handful of spinach serve as the sauce, which offers a mild, fresh flavor but proves easy to throw together. Feel free to use whatever short pasta you have on hand (we like tubular gemelli, but fusilli or even medium shells work well, too). And make sure you clean the leeks thoroughly before cooking; slice the onions down the middle and wash in a bowl of water. Grind a bit of fresh black pepper over each plate.