Clean, wash and break the beans into pieces. Peel onion and garlic and cut into cubes. Heat the oil in a pot. Fry the onion and garlic until transparent. Add the beans and fry briefly.
Deglaze with 1/8 litre water. Stir in vegetable stock and bring to the boil. Season with salt and pepper. Cover and cook over medium heat for about 15 minutes
Clean, wash and slice the tomatoes. Wash the thyme and pluck the leaves from the stalks. Drain mozzarella and cut into slices. Layer the bean vegetables and tomatoes in a flat ovenproof dish. Season with salt and pepper.
Sprinkle half of the thyme on top. Cover with mozzarella and sprinkle with remaining thyme. Bake in a preheated oven (electric range: 225 ° C/ gas: level 4-5) for 10-15 minutes until golden brown. Roast potatoes taste good with it