Add the butter and spring onions to the pan, and fry for 30 seconds. Pour in the oil, lemon juice and capers and heat for a further 30 seconds. Add the cooked pasta, reserved pasta water ...
lemon juice and zest, and capers, scraping up the browned bits from the bottom of the pan. Add the salmon to the pan, skin side down. Bring to a simmer and cook, occasionally spooning the sauce ...