The idea of a slightly sour lentil soup came from a dish we at had the Restaurant St Georg and was further reinforced by memories of soups from Romania.
Cook some finely diced smoked bacon in a bit of olive oil until it starts to take on some color. Add finely diced carrot and minced onion and garlic and cook until the vegetables soften. Add rinsed green lentils, finely diced starchy potatoes, a splash of white wine, chicken stock, a bay leaf, and a clove. Simmer until the lentils are tender; the potatoes will more or less dissolve. Add some cream and adjust seasoning. Add white balsamico in small portions until the sourness is at an appropriate level.
To go with this I did a salad of schnibbelbohnen (boiled until tender) and red cabbage (thinly sliced and then steamed until crisp-tender) dressed with minced onion, sugar, lemon juice, savory, cream, and rapeseed oil. After dressing it I let this sit for a couple hours to marinate.