Peel, wash and chop the potatoes. Peel and finely chop the shallots. Fry in 1 tablespoon of hot fat. Add potatoes and stock. Season with salt and pepper. Cook for about 15 minutes.
In the meantime wash and sort the spinach. Blanch briefly in boiling salted water, then drain. Add to the potatoes 3 minutes before the end of the cooking time. Add cream as well. Shortly before serving, puree lightly with a chopping stick, season to taste again.
Wash the fish and cut into portions. Season with salt and pepper. Turn lightly in the flour. Fry in hot oil while turning for 6-8 minutes. Sprinkle with lemon juice. Cut toast and bacon into small cubes.
Fry until crisp in the remaining hot fat. Serve everything garnished with lemon and lemon balm.