Rinse the sardines under running water to remove the salt; once boned slice them into fillets. Peel the onion, rinse it and once dried chop it finely with the peeled clove of garlic. Slice the broccoletti into florets removing the stalk, then rinse them well in cold water. Heat the oil in a pan, add the onion mix and fry until soft but not golden.Add the sardine fillets, stir with a wooden spoon then add the olives, stoned earlier. Cook the pasta in plenty of boiling salted water, 5 minutes before the pasta is ready toss the broccoletti in. Drain the pasta with the broccoletti al dente, mix them with the sardine and olive sauce, stir well and serve warm.