First put your pasta on to cook per the instructions on the pack. It usually takes between 9 and 11 minutes.
While the pasta is cooking, make up the the fish stock cube and the half of a fish stock pot with 400ml/1¾ cups of boiling water and set aside.
Spray a pan with some low calorie cooking spray then sauté the onions for about 5 minutes, until they are soft. Pour in the stock, then add the salmon, asparagus, parsley and lemon juice. Cover and cook for 5 minutes.
While the salmon and pasta are cooking, whisk together the egg, yolk and quark until smooth.
Drain the pasta and return it to the pan, then quickly stir in the egg/quark mix. Beat well until it's a smooth consistency, then add the salmon, asparagus and cooking liquid. Mix well then stir in half of the pecorino and a little black pepper.
Serve sprinkled with the remaining pecorino and a little chopped parsley.