Fill your kettle and boil it. Fill a large pan with water from your kettle, topping it up with more water if necessary. Add a pinch of salt, cover and bring back to the boil. While the pan of water is coming up to the boil, chop the chicken breast mini fillets into bite-sized pieces.

Place a deep frying pan or wok on a medium heat and add 1 tbsp olive oil and the chicken. Fry for 5 mins, turning every so often, till golden brown.

While the chicken fries, peel and finely slice the red onion. Trim the flat beans and chop them on the diagonal to make 1-2 cm-thick pieces. The water should be boiling by now, so add the penne. Simmer for 6 mins. After 6 mins, add the flat beans and simmer for a further 4-5 mins till the pasta and beans are tender but still have a bit of bite.

Meanwhile, add the onion to the chicken. Season with a pinch of salt and fry, stirring for 5 mins till softened and a little browned. Finely grate the zest from the lemon.

When the red onion has softened and is slightly caramelised, add half the lemon zest and half the rocket to the pan. Cook and stir for 2 mins to wilt the rocket.

Scoop a ladleful of water out of the pasta pan, drain the penne and beans and add them to the chicken. Add half the jar of pesto and stir to mix. If it seems a little dry, add 1-2 tbsp pasta water (or more if you think it needs it). Squeeze over a little lemon juice. Divide the pesto chicken penne between 2 plates, top with the remaining lemon zest and rocket and serve straight away.