In a search for seasonal vegetable side dishes that don't involve squash or sweet potatoes, I've stumbled upon a new love: winter greens. Chard, kale, escarole, and their cousins - in addition to being ridiculously good for you - brighten up dull winter plates with splashes of vibrant color that our eyes have been longing for since summer. Kale is my new favorite: it's dark, flavorful, and slightly chewy, even when it's cooked. And this recipe is my favorite way to prepare it: boiling the greens first, then sautéeing them with a little olive oil, onion, garlic, and crushed red pepper for heat, then finally, finishing with a splash of red wine vinegar. The end result is a dish that tastes leafy and healthy, a little spicy and a little tangy and just...really, really good. And the best part? Not only does it taste really good - knowing how many vitamins and nutrients you're giving your body, you somehow feel virtuous eating it. Not too bad for a humble side of greens.