Peel and finely dice 1 onion. Melt the fat in a pot. Add diced onion and millet and fry in it. Add 1/2 litre stock, bring to the boil and cook for 20-25 minutes, stirring once.
Let the millet cool. Roast pine nuts in a pan without fat, remove. Peel kohlrabi, cut into small cubes and cook in little salt water for about 10 minutes. Clean, wash and cut the zucchini into pieces.
Peel and finely dice 1 onion and garlic. Heat 1 tablespoon of oil in a pan. Fry the onion, garlic and zucchini. Add the tomatoes in the juice. Chop the tomatoes slightly. Add 1/8 litre stock and bring to the boil.
Drain and fold in the kohlrabi. Cut feta cheese into small cubes. Mix the millet mixture, sheep's cheese, pine nuts (except for 1 teaspoon for sprinkling), egg, thyme and 2 tablespoons of breadcrumbs and form 8 meatballs.
Place 5 tablespoons of breadcrumbs on a flat plate and turn the meatballs in it. Heat 4 tablespoons of oil in a pan. Fry the meatballs for about 10 minutes, turning them over. Arrange the meatballs and vegetable sauce on plates and add 1 tablespoon of crème fraîche to each.
Garnish with thyme and remaining pine nuts.