Clean and wash the leek, cut it in half lengthwise and cut into pieces. Mix bread spread, breadcrumbs and egg. Wash the schnitzel, dab dry. Heat oil in a pan. Fry the escalopes briefly on both sides.
Season with salt. Spread cheese mixture on the escalopes, sprinkle with thyme. Place on a baking tray and cook in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 8-10 minutes. In the meantime, heat the fat in a pot. Brown the leek in it. Add stock, bring to the boil and cook for about 5 minutes. Bind with sauce thickener. Bring 1 litre of water to the boil, remove from the heat and allow to cool for 1 minute. Stir in the puree flakes.
Add stock, bring to the boil and cook for about 5 minutes. Bind with sauce thickener. Bring 1 litre of water to the boil, remove from the heat and allow to cool for 1 minute. Stir in the puree flakes. Arrange schnitzel, leek and puree on plates. Garnish with parsley