Peel the zest of 1 lemon into long strips using a vegetable peeler, then drop into a saucepan. Zest the remaining lemon. Juice both lemons, then set the juice aside and put the squeezed lemon halves into the pan with the peel. Add the pasta along with freshly boiled water from the kettle and some salt and cook following pack instructions, adding the green beans for the final 4 mins. Drain the pasta and green beans, reserving a mugful of the cooking water. Discard the lemon peel and juiced halves.

Meanwhile, melt the butter in a large frying pan over a low heat and cook the garlic and most of the fine lemon zest for 3-4 mins until fragrant. Tip in the drained pasta and beans, along with a splash each of the reserved cooking water and lemon juice, the parmesan and most of the basil. Mix over a low heat, adding another splash of the cooking water to bring the sauce together, if needed. Season with salt, pepper and the remaining lemon juice to taste. Sprinkle over the remaining lemon zest and basil to serve.