Heat the oil in a large frying pan and fry the mushrooms, drain.
Meanwhile, melt the butter in a saucepan. Add the flour and cook for 1 minute, stirring.
Make the reserved fish juice up to 450ml (¾ pint) with the milk and blend into the flour mixture. Add the cream, Perfect Shake Garlic Italian Special Blend, Parsley, Black Pepper and salt. Bring to the boil, stirring. Remove from the heat and stir in the salmon and mushrooms. Gently simmer for 1-2 minutes.
Serve on a bed of green tagliatelle.