The type of greens you choose will make a difference. Choose from chard, spinach, beet greens, mustard greens, collard greens, watercress, turnip greens, etc. We found that turnip greens are very strongly flavored and made the soup somewhat bitter, whereas chard, spinach, and beet greens are on the sweeter end of the spectrum. My favorite version is made with spinach and collards.
I adapted this slightly from the cookbook version and I would expect whoever makes it to add their own touches as well.
2 bunches greens, washed, tough stems removed, torn into pieces
2 bunches green onions (scallions), washed and the root ends trimmed
2 bunches cilantro, washed
Place all of the above in a large pot with 3 cups of water and a teaspoon of salt. Bring to a boil, reduce heat, and simmer about 30 minutes.
1 large onion, chopped
5-6 cloves garlic, chopped
Saute the onion slowly until caramelized, about 25-30 minutes, stirring often. At the last, add the garlic and let it sizzle briefly. Then add the whole thing to the greens and let simmer another 10 minutes.
Let cool a few minutes, then puree in a blender or food processor in batches. You will need more liquid to do this and you can use water or broth, as you prefer.
Return soup to pot. Heat gently and add a tablespoon of lemon juice, a good sprinkle of cayenne, salt and pepper to taste. Then season as you think it needs it - a hit of balsamic vinegar, nutmeg, and some cumin can really make this soup sing.
Garnish with some feta or blue cheese or a drizzle of olive oil.