Preheat oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2). Wash leg, dab dry. Season with salt and pepper. Place on an oiled fat pan or in a flat roasting pan. Braise in a hot oven for 2 1/2 - 3 hours.
Peel and quarter the onion. Peel, wash and coarsely chop 2 carrots. Spread both with the cinnamon sticks around the leg. Fry for 15 - 20 minutes, turning occasionally. Then gradually add 3/8 - 1/2 l water.
Top the leg with the roast stock from time to time.
Peel or clean and wash the remaining vegetables. Cut carrots into pieces, cauliflower into florets. Steam both in approx. 3/8 l salt water covered with 1 pinch of sugar for approx. 10 minutes. Cook the sugar snap peas for the last 2 minutes.
Drain everything and collect the vegetable water.
Remove the leg of lamb, the meat should fall off the bone and be butter-soft. Dissolve the roast with the vegetable water and pour it through a fine sieve into a pot. Bring to the boil. Stir starch and 3 tbsp. water until smooth, add to the sauce and simmer for 3-4 minutes.
Season to taste with salt, pepper, 1/2 teaspoon turmeric and cinnamon.
Remove the meat from the bone and cut into bite-sized pieces. Re-heat with the vegetables in the sauce at low heat. Season to taste again. Basmati rice tastes good with it.