Place
the scallops, onion, mushroom & seasoning in
a saucepan and
add enough white wine to cover.
Simmer
gently until the scallops are cooked (approx 5
minutes).
Strain,
reserving the white wine to make a sauce. Place
the scallop mixture
to one side and keep warm.
Melt
the butter in a saucepan and add the flour. Mix
until it forms a ball.
Remove from heat.
Slowly
and gradually add the white wine and enough milk
until a
runny sauce is formed.
Return
to heat and bring to the boil. Lower the heat and
stir well until the
sauce thickens.
Add
the scallop mixture and prawns to the sauce to
heat through.
Place
in the scallop shells and top with the
breadcrumbs and grated emmental.
Grill
until golden brown and serve with warm crusty
bread.