For the pasta with pesto rosso and salmon, cook the pasta according to package directions until al dente. Then drain. Add the pesto to a slightly heated pan together with the mascarpone and the cooking cream. Mix everything together well and heat.
Heat some butter in another pan and fry the salmon fillet on the skin side until crispy. Shortly put it on the other side and fry it very briefly (be careful that it still stays juicy on the inside. Season with salt and pepper.
In the meantime, clean the spring onions and cut them into fine rings. Add the pasta to the sauce in the pan and mix everything well. Season with salt and pepper if necessary.
Arrange the pasta on warmed plates, place the salmon fillet on top and garnish with spring onions.