Bring water, wine, butter and mixed herbs (dill, chervil, chives, parsley and tarragon) to a boil in a large saucepan. Squeeze half a lemon and add the juice. Put in the trout and let it steep for 15 minutes in a closed pot on the lowest possible heat. Lift out, arrange on a plate and keep warm.

Whisk the cream with cornstarch, stir into the fish sauce and bring to the boil. Reduce by half, then season with salt and pepper.

Pour the sauce over the trout. Jacket potatoes also taste good.