Peel the garlic. Peel onions and cut into slices. Wash and clean the tomatoes and cut into thick slices. Wash thyme, shake dry, put 1-2 stems aside for garnishing. Cut some stems only in half, pluck the leaves from the remaining stems. Peel, wash and halve the potatoes. Spread the potatoes, onions and tomatoes on a fat pan of the oven or in a large roasting pan. Sprinkle with salt, pepper and 3/4 of the thyme. Sprinkle with 3 tablespoons of oil
Wash the meat and dab dry. Rub all around with salt and pepper. Mix lemon juice, chilli flakes and 3 tbsp. olive oil and brush the meat all around with it. Cut 12 small holes with a sharp knife into the top of the meat. Put the garlic in. Place the meat on the vegetables
Roast in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 3 1/2 hours. Pour on broth halfway through the roasting time. Grate cheese finely. Mix cheese, breadcrumbs, remaining thyme and 1-2 tbsp. oil. Place on the roast and fry at the same temperature for another 15-20 minutes
Remove from the oven, garnish with thyme stalk