My wife and I focused on good dirt this year when we planted our backyard garden in some raised beds I built with a friend. Good soil really matters. Check out these mustard greens. There are some flowers in the picture - that's because they grew too much before harvesting and are starting to mature. I didn't know what to do with them so just sort of marveled at them.
It turns out that they are just delicious cooked the way I do lots of greens, including spinach, chard, kale, beet greens and dandelion greens. Collard greens need a bit more work. Simply chop off the tough stems and save for vegetable stock along with other scraps, stack the leaves, roll them up then slice them thinly with your favorite newly sharpened chef's knife. Saute them in a BIG skillet (they start out with a big pile but shrink down). (First, I heat the pan, add some minced garlic cloves and a sprinkling of crushed red chilies, then add whatever greens.) Season to taste with a little salt and freshly ground pepper. A huge pile of greens will serve two people. These were really good with about 20 minutes total between garden and plate. I encourage you to plant some greens today. If you don't have a lot of space, they will also grow well in a large pot.