Cook the tagliatelle according to the instructions on the packet.
Rinse the salmon fillet briefly, pat dry and cut into fine strips.
Bring the cream and 200 ml milk to the boil. Mix the starch with the rest of the milk until smooth and stir in so that the mixture thickens. Then stir in the mustard and lemon juice. Add the salmon pieces and cook in them.
Season with salt and pepper and serve with the ribbon noodles.