Bring a large saucepan of salted water to the boil, add the tagliatelle and cook until al dente.
Meanwhile, heat the extra virgin olive oil in a large frying pan, add the garlic and chilli and sweat over a medium heat for a minute or so.
Add a ladleful of the pasta water, then the butter and allow to melt, before adding the lemon juice.
Drain the tagliatelle and, using a pair of tongs, add it to the pan and mix well. Stir in the Parmesan and parsley.
Serve immediately, sprinkled with the lemon zest and extra Parmesan, if desired.
