Cook the pasta according to the instructions on the packet.
Core and finely dice the cucumber. Pluck the trout into small pieces and cut the spring onions into rings.
Bring the wine and the broth to the boil, add the cucumber cubes and cook for about two minutes. Add the cream, lemon juice and mustard and let it reduce. Salt and pepper the sauce.
Drain the pasta and add the spring onions, fish and dill to the sauce and bring to the boil briefly.