Wash the leg and dab dry. Season all around with salt and pepper. Place the leg on a rack over the fat pan of the oven. Cook in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 1 hour.
Meanwhile wash herbs, chop them separately. Grind 60 g almonds, pine nuts and a slice of toast. Mix parsley, basil, almonds, pine nuts, toast, olive oil and egg to a paste. Cut onions into slices.
Place the onion slices and lamb bones on the fat pan. After another 30 minutes, deglaze the roast with 1/2 litre of water and wine. Spread the paste over the roast and cook for about 30 minutes. For the dumplings, toast the rest of the toast and dice finely.
Form small dumplings out of the dumpling dough and add diced toast. Cook the dumplings in boiling salt water for about 20 minutes, then drain. Peel, wash and cut carrots into small pieces.
Put into little boiling salted water. Season with 10 g butter and 1 pinch of sugar. Cover and cook for about 15 minutes. Melt 20 g butter in a pan. Fry 30 g almonds briefly. Add dumplings and chervil and toss in.
For the sauce, pour frying mixture through a sieve into a pot and bring to the boil. Stir cornflour and 3 tablespoons of cold water until smooth, thicken the sauce. Bring to the boil again. Season to taste with salt and pepper.
Refine with cream. Serve everything garnished with basil.