Clean and wash the leek and cut into fine rings. Heat 2 tablespoons of oil in a large pan. Fry the potato noodles in portions all around for about 5 minutes. Remove.
Heat 1 - 2 tablespoons of oil in the frying fat. Fry the mince in it until crumbly. Fry the leek briefly. Season with marjoram, cayenne pepper and a little salt. Add 1/2 L water and stock. Bring to the boil and melt the processed cheese in flakes. Simmer over high heat for about 5 minutes. To taste.
Put potato noodles and leek mince sauce in a large, greased baking dish. Rub the cheese over it. Bake in a preheated oven (top / bottom heat: 200 ° C, convection: 175 ° C, gas: level 3) for about 20 minutes until golden brown.