Preheat the oven to 220°C/200°C fan and line a large baking tray with baking paper.
Take a large piece of baking paper, place a chicken breast on the left half of the paper and fold the right half of the paper over the top. Whack the chicken with the end of a rolling pin until it’s an even thickness all over. Set this chicken breast aside and repeat with the remaining chicken. Then cut each breast in half so you have eight smaller pieces in total.
Take three wide, shallow dishes. In one, mix the flour, dried oregano, a pinch of salt and a pinch of ground black pepper.
In the second dish, mix the egg with a pinch of salt.
In the third dish, place the panko breadcrumbs.
Dip each chicken piece in the flour, then the egg and finally the breadcrumbs, shaking off the excess. Place onto the lined baking tray spacing them a few centimetres apart. Drizzle with half of the oil, then flip them all over and drizzle with the remaining oil.
Bake for 25–30 minutes, flipping them over halfway through the cooking time, until golden and crisp.
Cut the mozzarella into eight slices and place one slice onto each piece of chicken. Return to the oven for five minutes so that the cheese can melt.
Remove from the oven and top each piece of chicken with a little pesto. Serve in the ciabatta rolls with the rocket and tomatoes.

Joe Wicks’ chicken burger recipe is perfect for post-workout sunshine