A classic of Greek cuisine, avgolemono sauce is made with chicken broth, egg yolks and lemon juice. Avgolemono soup contains more broth and includes rice.You can use any kind of kale in this recipe. Be sure to remove the center spine of the leaves before chopping. Following the directions carefully will avoid curdling the egg yolks when they are mixed with boiling broth.
In a large saucepot, heat the oil, onions and garlic until aromatic and tender. Add the chopped kale; stir and then add chicken broth and salt. Bring to boil, reduce heat and simmer, uncovered, for 40 minutes. Drain and reserve the broth. There should be a cup or more to use in the avgolemono sauce. Keep the kale warm.
In a medium saucepot, bring 1 cup of the broth back to a boil.
Whisk the egg yolks for about a minute in a medium bowl, and then gradually pour half the boiled broth into the bowl. Next, gradually pour the egg-broth mixture back into the original pot of chicken broth, whisking it as you do. Season with lemon juice and salt.
Add the kale, fresh dill and mint mix to the sauce and serve.