Wash and drain the vegetable onions and place them on a baking tray lined with baking paper. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 1-1 1/4 hours. Let the roasted onions cool down for 20-30 minutes, cut off the stem and peel the onion skin. Coarsely dice onions (net weight approx. 800 g) and place in a pot. Add 250 ml hot stock and puree finely.
Pour in the remaining stock, bring to the boil and simmer at low heat for about 5 minutes. Stir crème fraîche into the soup, season with salt and pepper. Wash the basil, shake dry and pluck off the leaves. Serve the soup in deep plates, add 1-2 slices of Parma ham to the soup and sprinkle with basil leaves. Add freshly ground pepper to the soup as desired
Waiting time approx. 20 minutes