Cook the pasta in salted water that is sufficiently boiling for about 8 minutes, drain and allow to drain. Grate parmesan and gouda finely. Dice gorgonzola roughly. Bring stock and milk to the boil and stir in processed cheese.
Gradually add the remaining cheese to the sauce, stirring constantly, and melt. Wash the marjoram, dab dry and pluck the leaves from the stalks, except for some for garnishing. Chop the marjoram roughly and stir into the sauce.
Wash the salmon, dab dry and cut into bite-sized pieces. Season with lemon juice and salt. Clean and wash spring onions and cut them diagonally into pieces. Fill noodles, salmon and spring onions into portion moulds and pour the cheese sauce over them.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 20 minutes. Garnish with marjoram and serve immediately.