Add onion, carrot, and celery. Saute until onion starts to soften, about 5 minutes
Add stock, bay leaf, thyme, and sweet potato
Cover and boil gently until sweet potato is tender, about 15 minutes
Add buckwheat groats, cover and simmer until cooked, about 10 minutes
Add salt & pepper to taste
Add turkey and kale
Stir in the lemon juice, remove from heat and serve hot.
Notes
If you will have leftovers of this soup, cook the buckwheat separately, adding to the soup before serving. (Like rice or pasta, the groats will absorb all of the liquid if allowed to sit).To make this buckwheat soup with fresh turkey or chicken, add cubed raw turkey or chicken when the stock is added to the pot.If you can't find kasha, or toasted buckwheat, you can toast the raw buckwheat groats yourself in a pan over low heat for about 10 minutes, shaking the pan often. The groats are toasted when they turn golden brown.