Chop the onions and sauté them in oil. Add the peeled tomatoes with the liquid and the liquid from the beans (not the beans themselves!) And simmer for about 10-15 minutes.
Then puree into a sauce with the hand blender. Add the stock cube and the sliced meatloaf. The whole thing must now simmer for about 1 - 1.5 hours over medium heat.
About half an hour before the end of the cooking time, add the potatoes and beans cut into bite-sized pieces. Season with salt and pepper at the end. Baguette goes well with it.