Open the scallops (fresh scallops should be heavy and closed) and remove the scallop meat. Use the orange-red roe (Corail) according to taste. Rinse mussel flesh and roe briefly, dab dry.
Preheat oven (electric cooker: 225 °C/circulating air: 200 °C/gas: see manufacturer).
Peel and finely dice the shallots. Melt butter in a pot. Sauté shallots in it. Dust with flour and sweat lightly. Deglaze with wine and cream and bring to the boil. Simmer while stirring for 3-4 minutes.
Wash the chervil, shake dry, chop finely and stir into the sauce. Season to taste with salt and pepper.
Wash out the deeper mussel shells, dry them and spread them on a baking tray (so that they do not tilt, possibly put them in some salt). Put the mussel meat and roe back into the shells. Spread sauce over them.
Cook in a hot oven for 10-12 minutes. Baguette tastes good with it.