Cut the chicken into very small pieces using a sharp knife. You can use a food processor, but pulse so it doesn’t turn into a paste. Put in a bowl and add half the lemon zest, half the ricotta, half the parsley, the breadcrumbs and mix together. Add the 2 tbsp milk, the egg and a good pinch of seasoning. Mix again.
Dust a plate lightly with flour. Wet your hands, take a golf ball-sized piece of the meatball mixture and roll into a ball. Set on the floured plate and repeat until all the mixture has been used up.
Heat a heavy-based frying pan over a medium heat, add the oil, then the meatballs, ensuring they don’t touch each other. Cook for 10-15 mins, turning so they brown on all sides. Transfer to a plate.
Meanwhile, heat a large pan of salted water and add the linguine. Cook following pack instructions, and 3 mins before the end of the cooking time, add the green beans. Drain, saving the pasta water. Rinse the linguine and beans under cool water to stop them cooking further.
Add the remaining ricotta to the frying pan, breaking it up as much as possible. Pour in the 100ml milk and 2 tbsp of reserved pasta water, then cook down to thicken slightly for a couple of minutes. Add the pasta, beans and remaining lemon zest and parsley. Season to taste, mix in the meatballs and serve.