Cut the potatoes into round slices. Season the ribs with soy sauce, savory, paprika and black pepper. Rub them well, as well as the potatoes, with the sauce and a little pepper.
Cut the leeks into round slices. Arrange some potatoes, a rib and leek slices on a sheet of foil. If needed, sprinkle on additional spices.
Sprinkle with a little olive oil and wrap well with the foil. Put the foil packets in the oven for about 50 min. If you'd like them to have a crust, open the foil toward the end and let them crisp.