For the oxtail ragout, peel the carrots and cut them into pieces. Clean the leek, cut into rings and wash. Wash thyme and shake dry. Rinse oxtail pieces cold and dab dry
Heat the oil in a frying pan. Fry oxtail pieces over high heat while turning them over. Season with salt and pepper. Remove the meat. Fry the carrots and leeks in a roasting pan. Add tomato paste and spices and sauté briefly. Put the meat back into the roaster. Fill up with red wine, bring to the boil and reduce by half. Add stock, bring to the boil, cover and simmer over medium heat for about 2 1/2 hours. Stir from time to time
For the red cabbage roll, wash the potatoes thoroughly and cook them in boiling water for 20-25 minutes. Drain, peel, press through a potato press (or grate finely) and let cool. Mix potatoes, fat, egg yolks and flour well. Season well with salt, pepper and nutmeg
Meanwhile clean the red cabbage, halve it and cut out the stalk in a wedge shape. Boil water in a large pot. Add the cabbage. After about 5 minutes, remove the cabbage and cut off the outer leaves. Repeat the process and remove a total of 12-14 large leaves. Dab the leaves dry and cut the thick ribs flat. Lay out cabbage leaves on the work surface overlapping to form a rectangle (30 x 35 cm). Carefully spread the potato mixture over it and smooth it down. Add the cranberries in patches. Roll up the cabbage leaves from the longer side. Wrap first in cling film, then in aluminium foil and close tightly. Cling film must not stick out. Cook the roulade in a preheated oven (electric cooker: 175 °C/ circulating air: 150 °C/ gas: see manufacturer) for 50-60 minutes. Take the roulade out of the oven, remove foil. Leave the roulade to rest for a short time (roulade is still a little soft immediately after removal. It should therefore rest for a few minutes so that it can be cut better).
Remove the meat from the sauce and cut it from the bone. Remove tendons and cartilage slightly. Put the meat back into the sauce and season with salt and pepper. Arrange roulade slices and ragout together