By thinking of vegetables in three wildly general categories—greens, tender, and hard—all you need is this recipe and the variations that follow to prepare and cook virtually everything. The “greens” category includes the most delicate, like watercress, spinach, and arugula, as well as those that require longer cooking, like collards and escarole. What I call “tender” vegetables are those that are firm but pliable when raw: celery, green beans, asparagus, snow peas, sugar snap peas, broccoli, cauliflower, and mushrooms, and those that fit the description when you chop or slice them, like eggplant, zucchini, cabbage, onions, leeks, shallots, and fennel. Everything else is “hard”: root vegetables, tubers (like potatoes), and winter squashes. For each vegetable in a category, you control how long it takes by choosing how to cut or slice it. Even hard vegetables like beets and sweet potatoes will cook relatively quickly when they’re cut in pieces less than 1 inch thick; they’ll cook fastest if you grate them. Making peace with the peels—which are nutritious and can actually be delicious—saves you several minutes, prep time. Let’s get right to it.