Start by making the tomato sauce. Heat the olive oil in a large pan, add the onion and garlic, cook until soft, approx 5 minutes. Add tomato puree and cook for a minute more.
Add the tomatoes and their juices, season, bring to the boil, reduce heat and simmer for approximately 10 minutes or until the sauce has thickened.
Heat a glug of olive oil in a frying pan, remove from heat and add garlic and fennel seeds, return to heat adding sardines, tomato sauce and chilli flakes. Cook for 2 minutes and season.
Finish with a handful of torn basil leaves, add freshly cooked spaghetti, a glug of olive oil and fold through a handful of rocket. Serve topped with shaved parmesan.