Wash the potatoes and cook for 20-25 minutes until soft. Cut purslane from the root, wash and drain well. Peel and finely chop the onion. Wash pike-perch, dab dry and cut into 8 pieces.
Drain the potatoes, rinse briefly in cold water and peel. Possibly halve or quarter the potatoes. Heat the oil in a pan. Season fish with salt and pepper and turn in flour. Fry the fish and lemon slices for approx. 4 minutes while turning, then remove from the pan and keep warm for a short time.
Meanwhile, heat 1 tablespoon of butter in a 2nd pan and lightly fry the potatoes for 3-5 minutes. In the fish pan, melt 2 scarce tablespoons of butter and fry the onion over medium heat for 2-3 minutes.
Add 2/3 of the purslane to the onion and sauté briefly (max. 1 minute). Season to taste with salt, pepper and a little nutmeg, then add the remaining purslane. Serve immediately with the fish, lemon slice and potatoes.
Garnish with 1 orchid each.