Add in pot: water, wine, shallot, bay leaf, a drop of oil, lemon and salt.
Add scallops sliced --they should be covered by the liquid. Simmer covered with a lid and let cook 5 minutes.
Remove scallops from cooking liquid and strain, keep the juice.
In frying pan, cook sliced mushrooms in the 2 tablespoons of olive oil for about 5 minutes, stirring often.
Prepare 4 dishes.
Divide scallops in each.
Divide shrimp in each.
Divide mushroom and put on top.
In medium saucepan, prepare white sauce: Melt butter over medium flame and pour flour in; stir. Reduce heat and add a bit at a time the cooking juice; stir and mix. Do this until the sauce is thickened.
Season with salt and pepper; add the cream.
Pour over the seafood equally.
Sprinkle with the breadcrumbs and dot with butter.