Peel the garlic and press it through the garlic press. Wash the rosemary. Wash the meat and dab dry. Brush with olive oil, garlic, salt and pepper. Fasten rosemary stems to the roast with kitchen string.
Place on the fat pan of the oven and cook in the preheated oven (electric: 200°C / gas: level 3) for approx. 50 minutes. In the meantime, peel onions and cut them into slices. Wash the potatoes thoroughly, cut them in half lengthwise.
Sprinkle the fat pan with coarse salt, add the onions and potatoes and cook for about 35 minutes. Clean, wash and cut the zucchini into coarse pieces and add 20 minutes before the end of the cooking time. Wash the lemon and cut into slices.
10 minutes before the end of the cooking time, deglaze the roast and vegetables with 1/4 litre water, add lemon and season with coloured pepper. Serve everything garnished with fresh herbs.