Wash and trim the purple sprouting broccoli, discarding any tough parts of the stalks and cutting them into 2cm pieces. Set aside. Bring a large saucepan of salted water to the boil and pour in the penne pasta. Boil the pasta for approximately 12 minutes until it is soft but still has a bite to it and then drain.
While the pasta is cooking, bring a smaller saucepan of water to the boil and blanch the purple sprouting broccoli for no more than three minutes. Drain and set to one side. Toast the pine nuts in a dry non-stick frying pan. The secret is to keep shaking them so they don't stick to the bottom and burn.
Take a heavy saucepan and heat the oil. Once hot, add the shallots, garlic and chilli along with a little salt and pepper and sauté until soft. Add the pasta, lemon zest and juice and toasted pine nuts and fry for a further three minutes. Add the purple sprouting broccoli and serve.