Wash the meat, dab dry and cut the rind crosswise. Season all around with salt and pepper and place on the fat pan of the oven. Wash lemon, rub dry and cut into slices. Place on the fat pan and roast in the preheated oven (electric: 175 °C/ gas: level 2) for about 1 1/4 hours. Add stock little by little. In the meantime clean, wash and slice the leek.
Peel, wash and cut carrots into small cubes. Heat the fat in a pot and sauté the vegetables for 10-12 minutes at low heat. Season with salt and pepper. Heat oil in a pan and fry the cashews until golden brown. Add to the vegetables and fold in. Remove the meat from the oven and let it rest. Pour the roast stock through a sieve and fill up to 1/2 litre if necessary. Bring to the boil. Add lemon jelly and stir in. Bind with sauce thickener and season with salt and pepper. Pour into a sauce boat and sprinkle with lemon julienne.
Remove the meat from the oven and let it rest. Pour the roast stock through a sieve and fill up to 1/2 litre if necessary. Bring to the boil. Add lemon jelly and stir in. Bind with sauce thickener and season with salt and pepper. Pour into a sauce boat and sprinkle with lemon julienne. Arrange the roast together with the vegetables and the lemon slices on a plate and serve. Serve with boiled potatoes