Buckwheat as a soup ingredient is uncommon here. I bought the buckwheat at a special store of Eastern Europe foods.
I sometimes use buckwheat flour for galettes or 15 % of buckwheat to wheat flour. It does not have gluten.
On my grocery shopping trip to France I bought free range chicken drumsticks and a huge bag of Pot au Feu vegetables.
Recipe for 3:
6 drumsticks, 1,2 l chicken stock, 1 tbsp oil
Cabbage, celeriac, leek, carrots, yellow beet, onion
Salt, pepper, dried majoram.
2 servings of buckwheat
Cook the buckwheat separately. After 12 min let them steam out.
Season the drumsticks and fry them in a little oil in a large pot. Chop all veggies and toss them in the pot. Fill up with chicken stock. Cook the soup for 25 min.
Add the buckwheat and check the seasoning. Finish with fresh ground black pepper.