Long, slow simmering makes collard greens an ideal choice for the slow–cooker. Because the greens give off so much of their own liquid, you only need to add a small amount of water to the slow cooker, which not only intensifies the flavor but retains more of the nutrients.
Using a sharp knife, trim the stems and inner ribs of the collard greens. Stack the leaves and cut them into 1-inch wide ribbons. Wash the greens and shake out excess water.2.
In a large pot, add the oil and cook the bacon over high heat, stirring occasionally, until browned and crisp, about 10 minutes. Add the onion, garlic and chipotle flakes, and cook, stirring, until softened, about 5 minutes longer. Add the collard greens in large handfuls, stirring and allowing them to wilt between additions. Add the tomatoes, vinegar, water and sugar. Season lightly with salt and transfer to a slow cooker. Cover and cook on high for 3 hours, until the greens are tender. Serve.
Grace Parisi is a New York City-based food writer, cookbook author and food stylist. Her book, Get Saucy, was nominated for a James Beard award. Her latest book, Quick Pickles comes out in Spring 2016. Follow her on Instagram and Twitter.