Sift the flour and a pinch of salt into a bowl and make a well.
Whisk the eggs, oil and 1 tbs. water in a jug, add gradually to the flour and mix to a firm dough.
Gather into a ball. (This can also done in food processor.)
Knead on a lightly floured surface for 5 mints., or untill smooth and elastic.
Place in lightly oiled bowl, cover with plastic wrap and set aside for at least 30 mints.
For the filling, Stir together the butter, garlic, parsley,scallops and prawn meat in a bowl, set aside
Roll out a quarter of the pasta dough at a time on lightly floured srface, or use a pasta machine, until very thin (each portion should be roughly 10 cm/4 inches wide when rolled.)
Place 1 tsp. of filling at 5 cm(2 inch) intervals down one side of each strip.
Whisk the extra egg yolk with 3 tbs. of water.
Brush along one side of the dough and between the filling.
Repeat with the remaining filling and dough.
Press the edges together firmly to seal.
Cut between the moulds with the knife or fluted pastry cutter.
Cook batches in a large pan of rapidlyboiling water for 6 mints.
Drain well and return to the pan to keep warm.
For the sauce, melt the butter in a pan over low heat.
Stir in the flour and cook for 1 mint. or until pale and foaming.
Remove from the heat and gradually stir in the combined milk,cream, and white wine.
Return to the heat and stir constantly until the sauce boils and thickens.
Reduce the heat and simmer for 2 mints.
Add the parmesan and chopped parsley and stir
Season to taste.
Remove from the heat, add to the ravioli in the pan and toss gently to coat.
