1. Heat a large soup pot or Dutch oven over medium heat. Once hot add the olive oil, swirl to coat the pan, and add the onions. Cook, stirring occasionally, until onions are translucent, about 5 minutes. Chop the collards while the onions cook.
2. To chop the collards, stack half the leaves on top of each other on a cutting board. Cut the stack lengthwise down the middle. Pick up one of stacks and place it on top of the other. Now cut the greens widthwise into ½-inch pieces. Repeat with the rest of the leaves.
3. Once the onions are translucent, add the garlic and red pepper flakes. Stir to combine and cook until fragrant, 30-60 seconds. Add the greens, smoked paprika, and salt and stir to combine.
4. Add the broth and bring the mixture to a boil. Once boiling, push the greens down into the broth, cover, and reduce the heat to low to maintain a strong simmer. Cook for 45-50 minutes, stirring halfway through, until the greens are cooked to your liking.
5. If you wish to serve the greens with their broth (pot liquor), add the vinegar, stir to combine, and serve. Alternately you can remove the lid, increase the heat to high and cook for about 5 minutes to cook most the broth off, before adding the vinegar and stirring well.

Source: Heather Pratt

Tips for What to Do With Excess Ingredients: Leftover broth can be used make soups or to cook grains or it can be frozen for later use. Smoked paprika gives a wonderful smoky flavor to anything you use it in, without any added heat. Try it in deviled eggs, soups, or spice rubs for meat.