Peel potatoes, wash them coarsely, dice them and cook in boiling salted water for 10 minutes. Clean, wash and quarter the zucchini lengthwise and cut into pieces. Peppers clean, wash and cut into pieces.
Peel, wash and slice the carrot. Clean, wash and cut leek into rings. Peel and chop onion and 1 clove of garlic. Rinse Roman pot with cold water. Drain potatoes and mix with vegetables, garlic and onions.
Put everything into the Roman casserole. Add peppercorns and berries. Wash and drain the fish. Sprinkle with half of the lemon juice, season with salt and pepper. Place the fillets on the vegetables.
Add wine and stock. Clean and wash spring onions and sprinkle over the fish. Cover and place in the cold oven. Cook for 1 1/4 hours (electric cooker: 200 °C/ gas: level 3). In the meantime, peel and finely chop the remaining garlic.
Mix crème fraîche and sour cream, lemon juice and garlic. Season with salt and pepper. Wash the herbs, chop finely and stir into the dip. Serve trout fillets on summer vegetables together with the dip.