Method

• 1.
  In a large bowl, whisk together the egg whites, soy sauce, cornflour, 1/2 tsp fine salt and a good grind of pepper, just until there aren’t any lumps, about 30 seconds.
• 2.
  Working with one breast at a time, place chicken between two pieces of baking paper and use a meat mallet or rolling pin to pound chicken so it’s about 1cm thick all over. Transfer to the egg white bowl, then repeat with remaining chicken.
• 3.
  Stir everything together gently to coat, and refrigerate to marinate for at least an hour (or overnight, if you’re getting ahead).
• 4.
  Meanwhile, to make the preserved lemon paste, place the lemon, lemon juice and 1 1/2 tsp salt flakes in a small saucepan with a lid set over medium-high heat.
• 5.
  Bring to a simmer, then lower heat to medium-low, cover and cook for 12-14 minutes, until rinds start to look translucent and juice has reduced by about half.
• 6.
  Set aside to cool slightly, then transfer everything to a small food processor and blitz until you have a smooth, spreadable paste. Set aside 21/2 tbs for the sauce, then store the rest in a sealed container in the fridge for up to 4 weeks (see note).
• 7.
  For the sauce, add the 21/2 tbs preserved lemon paste, stock, butter, garlic, sugar, turmeric and half the cumin to a medium saucepan, then place it over medium-high heat. Bring to a boil, then cook, stirring occasionally, for 15 minutes, or until reduced by about a third.
• 8.
  Measure out roughly 2 1/2 tbs of sauce into a small bowl, then add the cornflour and whisk until there are no lumps. Whisk this back into the sauce pot and cook for 1 minute, whisking continuously, until smooth and thickened slightly. Remove from the heat.
• 9.
  To cook the chicken, heat the oil in a large high-sided frypan over a medium - high heat. Once hot (a sprinkle of cornflour dropped into the oil should sizzle right away), fry two of the chicken breasts for 3 minutes per side, or until nicely browned and just cooked through. It should release easily from the pan with a little help from a metal spatula. Transfer to a paper towel-lined plate and repeat with the remaining chicken. It might spit, so turn down the heat if needed.
• 10.
  Discard oil from pan, add the lemon sauce and bring to a simmer over medium-high heat. Add back all the chicken and cook for just 3 minutes, gently turning halfway. Remove from heat and stir in half the lemon juice (30ml).
• 11.
  Transfer the chicken breasts to a large serving platter and pour the sauce all over. Sprinkle with the remaining cumin.
• 12.
  In a small bowl, toss together the shallot, coriander and remaining lemon juice, and spoon all over chicken. Serve with steamed green beans and broccolini.