Wash the meat, dab dry, cut the rind. Peel the vegetable onion and cut into slices. Put the roast on a fat pan, spread the onion slices all around. Cook in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 2 1/4 hours. Pour 500 ml of water on the onions after 1 hour and 250 ml of water after another 1/4 hour.
In the meantime, peel and wash the carrots, except for some green. Melt the butter in a wide pan (or in a roasting pan). Briefly sauté the carrots in it, season with salt. Dust with icing sugar and let it caramelize for about 5 minutes while turning. Scoop 250 ml frying stock from the fat pan. Mix with vinegar and 250 ml water. Deglaze carrots with it and simmer covered for about 8 minutes. Remove the basil leaves. Just before serving, toss in the carrots.
Scoop 250 ml frying stock from the fat pan. Mix with vinegar and 250 ml water. Deglaze carrots with it and simmer covered for about 8 minutes. Remove the basil leaves. Just before serving, toss in the carrots. Serve with parsley potatoes