Clean, wash and drain the spinach. Peel and finely chop the onion and garlic. Wash fish, dab dry and cut into cubes. Heat 1 tablespoon of oil in a large pot, fry onion and garlic, add spinach.
Meanwhile, prepare the pasta in boiling salted water according to the instructions on the packet. Drain, quench briefly and allow to drain. Add lemon zest, except for 1 tsp. for sprinkling, to the spinach. Season with salt and pepper.
Add stock and whipped cream, bring to the boil, stir in sauce thickener and bring to the boil briefly.
Heat 2 tablespoons of oil in a large frying pan, fry the fish cubes for about 3 minutes, season with salt and pepper and remove. Mix the noodles and fish with the spinach, heat up and season again with salt and pepper.
Sprinkle with lemon peel and serve.