Step by step recipe:

1. 5 min.

   The shellfish

   Clean and rinse 300 g cockles, 300 g mussels and 300 g clams.
2. 2 min.
   Pour 2 tablespoons olive oil into a large saucepan on high heat.
   
   When hot, tip in the shellfish and 200 ml dry white wine, then cover.
3. 4 min.
   Cook for 2 or 3 minutes until all the shells have opened.
   
   Remove them from the pan with a skimmer or araignée (spider) and transfer to a strainer or colander. Do not discard the cooking juices.
4. 2 min.
   Pour 3/4 of the cooking juices through a very fine strainer into a smaller saucepan.
   
   Discard the remaining quarter which is generally full of sand from the shellfish.
5. 20 min.
   Put the saucepan on low heat uncovered and leave the juices to reduce by 3/4.
6. 5 min.
   Meanwhile, remove and discard the shells and put the shellfish into a bowl.
   
   Set aside.
7. 8 min.

   The mushrooms

   Peel 500 g mushrooms, then chop.
8. 5 min.
   Pour 3 tablespoons olive oil into a frying pan on high heat.
   
   When good and hot, add the chopped mushrooms and sauté until browned.
   
   Important: do not salt until the end of cooking, otherwise the mushrooms will give off too much water.
   
   Set aside.
9. 15 min.

   The potatoes

   Peel and rinse 750 g potatoes, cut into fairly large chunks and cook in boiling water (start from cold to prevent them falling apart).
   
   Drain when cooked and set aside to keep hot.
10. 8 min.
    Pour 3 tablespoonsful of the reduced mussel stock into a small saucepan with 200 ml liquid cream.
    
    Do not salt (the mussel stock is already very salty, which is quite normal), but pepper generously, then leave to thicken on low heat, stirring from time to time.
11. 1 min.
    Tip the shellfish and mushrooms into the sauce, then check the seasoning and leave to wait on very low heat.
12. 3 min.

    The sole fillets

    Have your fishmonger prepare 500 g sole fillet for you. Salt and pepper on both sides.
13. 4 min.
    Melt 70 g butter in a large frying pan and let it froth.
    
    Lay the sole fillets in the pan and brown on both sides.
14. 
    During cooking, baste the fish with butter: Tip the pan at an angle so you can spoon up some of the butter and drizzle this over the fish (do this several times).
    
    Heat the plates you will be using to serve.
15. 5 min.

    To serve

    On each plate (it is important for them to be hot), lay 2 half sole fillets one on top of the other.
    
    Arrange chunks of potato alongside and pour a generous helping of the shellfish and mushroom sauce over.
    
    Garnish with a few leaves of parsley and serve immediately.