Preparation
Cut the leek into rings and keep the green.
Cut the tops of the fennel and cut the leaves into thin strips. Keep the tops of the fennel with the leek green.
Cut the potatoes into wedges and boil them for 5-8 minutes.
Drain the potatoes and let them steam out.
For the sauce
Chop the onion and garlic. Cut the center of the celery into rings.
Heat the onions and garlic in a hot pan with a little bit of butter. As soon as the garlic starts to brown, add the celery. Turn this on and then add the tops of the fennel and the leek greens. Deglaze with white wine. Add 1.5 liters of water and let it simmer for an hour until you have a nice vegetable stock. Strain the stock as soon as it is tasty.
Then make a roux. To do this, melt the butter in a saucepan. Once the butter has melted, add the flour and stir well. The roux is ready when it starts to stick to the bottom of the pan. Then add the stock in parts to the roux with a whisk. Season the sauce with the soy sauce and a little pepper. Put the sauce on low heat. Make a mixture of the egg and cream. Then add the egg mixture to the sauce. Stir well immediately. If the sauce is a little too thick, thin it out with a little cream or water. Don't let the sauce boil!
For the potatoes
Heat some butter in the medium-sized pan and add the pre-cooked potatoes. Then add the leek rings and sauté them. Continue the steps by adding the fennel, salt, pepper and a splash of white wine. Place the potato mixture over low heat, turning occasionally.
For the fish
Take a frying pan and put a knob of butter in it. Place the fish with the skin in the bubbly butter. Turn the fish when the body is golden brown. Add another knob of butter and spoon it over the fish from time to time. Once the fish is almost cooked, add a dash of soy sauce and spoon this over the fish as well. Remove the fish from the pan and let it rest for a while. Place the cockles in the used pan of the fish, which still has all the flavor and butter in it. Stir well and add a splash of white wine to open the clams.
Plating
Spoon a few heaped spoonfuls of potato mixture into a deep plate. Then place the fish on top. Add a generous amount of sauce to the plate. Then put some cockles on the plate and sprinkle some chopped parsley over the dish.