Wash the plaice fillets, sprinkle with lemon juice (keep some juice) and season lightly with salt and pepper. Roll up the fillets and fix them with wooden sticks. Bring 1/4 litre water, wine, peppercorns and bay leaf to the boil.
Put the rolls in and let them simmer at low heat for about 5 minutes. In the meantime, peel and finely dice the onion. Heat the fat and sauté the onion in it. Pour on cream and let it boil down a little.
Remove the rolls from the stock. Remove wooden sticks and place them in an ovenproof dish. Arrange the crabs around it. Add 100 ml fish stock to the cream. Whisk the egg yolks, mix with some hot sauce and add to the sauce.
Do not let it boil anymore. Season with salt, pepper and lemon juice. Pour the sauce over the rolls and bake in a preheated oven (electric cooker: 225 ° C/ gas: level 4) until golden brown. Garnish with puff pastry fleurons and dill.
Served with leaf spinach with mushrooms.