Gently shallow fry the onions in the butter and oil until golden, add the peas and cook for approximately 3 minutes.
Add the salmon, season with salt and pepper and cook for a further 2 minutes maximum. Add in the cream and cook for another 2-3 minutes.
In the meantime, cook the pasta in salted boiling water until al dente. Drain then add to the sauce and mix well on a low heat allowing the sauce to thicken. Serve immediately with some freshly ground pepper.