Peel the potatoes and thinly slice them, then rinse them in cold water to remove excess starch. Peel and crush (mince) the garlic, peel and thinly slice the onions and slice the tomatoes. Trim any surplus fat off the steaks.
Drizzle 1 tablespoon of the oil into a casserole or pie dish and rub all over. Place the steaks on the bottom of the dish, pour the stock over then scatter over about half of the garlic. Create a layer of onion and tomatoes followed by a layer of potatoes on top. Season well with salt and freshly ground black pepper, then repeat the layers, finishing with a layer of potato.
Drizzle with the remaining oil and then cover the casserole with a tightly fitting lid (if you are using a pie dish, seal with a double layer of foil). Cook in a preheated moderate oven (Mk 4 - 350ºF - 180ºC) for 2 hours, then remove the lid or foil and turn the oven up to hot (Mk 7 - 425ºF - 220ºC) and cook for a further 30 minutes or until the top is golden brown (check it at 20 minutes). Serve hot with lovely Peppered Cabbage.