- 1/4 cup extra-virgin olive oil
- 12 ounces Spanish chorizo, cut into 1/2-inch pieces
- 1 onion, chopped fine
- 4 garlic cloves, minced
- Salt and pepper
- 1/4 teaspoon red pepper flakes
- 2 pounds potatoes, peeled and cut into 3/4-inch pieces
- 4 cups chicken broth
- 4 cups water
- 1 pound collard greens, stemmed and cut into 1-inch pieces
- 2 teaspoons white wine vinegar
Heat 1 tablespoon oil in Dutch oven over medium-high heat until shimmering. Add chorizo and cook, stirring occasionally, until lightly browned, 4 to 5 minutes. Transfer chorizo to bowl and set aside. Reduce heat to medium and add onion, garlic, 1 1/4 teaspoons salt, and pepper flakes and season with pepper to taste. Cook, stirring frequently, until onion is translucent, 2 to 3 minutes. Add potatoes, broth, and water; increase heat to high and bring to boil. Reduce heat to medium-low and simmer, uncovered, until potatoes are just tender, 8 to 10 minutes.
Transfer 3/4 cup solids and 3/4 cup broth to blender jar. Add collard greens to pot and simmer for 10 minutes. Stir in chorizo and continue to simmer until greens are tender, 8 to 10 minutes longer.
Add remaining 3 tablespoons oil to soup in blender and process until very smooth and homogeneous, about 1 minute. Remove pot from heat and stir pureed soup mixture and vinegar into soup. Season with salt and pepper to taste, and serve. (Soup can be refrigerated for up to 2 days.)