Soak the beans overnight in plenty of cold water. The next day boil them up in the soaking water, add broth and 1 teaspoon of thyme and cook for about 1 1/4 hours. Peel, wash and dice the potatoes.
Wash and dice the tomatoes. Clean and wash spring onions and cut into rings. Heat the oil in a pan and fry the potatoes for about 20 minutes, turning them over. Add the remaining thyme and season with salt and pepper.
Drain the beans and add to the potatoes with the spring onions and tomatoes. Peel the garlic, press it through a garlic press and mix it with the beans. Let everything braise well and season again with salt and pepper.
Crumble the feta cheese and sprinkle over the beans before serving.