Peel and chop the onions. Clean, wash and cut the leek into rings. Peel and chop the carrots. Cut turkey into cubes. Heat oil in a roaster. Brown the turkey meat all around.
Season with salt, pepper and marjoram. Dust with flour. Add onions, carrots and leek and fry briefly. Deglaze with wine and stock, bring to the boil. Cover and stew for 10 minutes. Bring 3/8 litres of water and 1/2 teaspoon salt to the boil. Add milk, stir in puree powder. Remove from the heat and allow to swell for 1 minute. Stir again. Put the turkey ragout in a greased casserole dish. Add mashed potatoes and bake in the preheated oven (electric cooker 200 °C/ convection oven 180 °C/ gas: level 3) for 10-15 minutes.
Bring 3/8 litres of water and 1/2 teaspoon salt to the boil. Add milk, stir in puree powder. Remove from the heat and allow to swell for 1 minute. Stir again. Put the turkey ragout in a greased casserole dish. Add mashed potatoes and bake in the preheated oven (electric cooker 200 °C/ convection oven 180 °C/ gas: level 3) for 10-15 minutes. Wash parsley, chop finely and sprinkle over the casserole. Serve garnished with marjoram