Cook pasta in boiling salted water according to package instructions until al dente. Quench and drain well
Heat cream cheese, stock, lemon peel and thyme while stirring. Season with salt and pepper
Sort, clean, wash and drain the spinach. Finely dice the shallots. Dice salmon fillet. Heat 1 tablespoon of oil in a frying pan. Brown the salmon fillet all around. Season with salt and pepper and remove. Steam shallots in salmon oil until translucent. Add spinach and let it collapse. Season with salt, pepper and nutmeg
Cut beetroot and goat gouda into small cubes. Fill pasta, spinach, salmon and beetroot in 2 casseroles. Pour cheese sauce over them. Sprinkle with cheese cubes. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 20 minutes