Preheat the oven grill (broiler) to high.

Heat the olive oil in a large, deep, heavy-based pan over medium heat. Sprinkle the chicken with the salt and pepper on both sides and cook for 5–6 minutes, or until the chicken is just cooked, turning once halfway through. Remove and set aside on a plate to rest. Once cool enough to handle, shred the chicken using two forks.

Use the ¼ cup (60 ml) of water to deglaze the pan if needed, to scrape up any sticky bits. Keeping the pan over medium heat with any pan juices, add the butter, onion and garlic. Cook, stirring, for 1–2 minutes.

Add the leek and cook, stirring, for 3–4 minutes or until softened.

Add the flour and cook, stirring, for 1 minute until well incorporated.

Pour in the chicken stock and stir until combined.

Add the thickened cream, Italian mixed herbs, broccoli, salt (see note 1) and pepper. Bring to a simmer.

Using tongs, add the cut lasagne squares, ensuring they are completely submerged in the sauce and as evenly distributed as possible.

Reduce the heat to low, cover and simmer for 6–7 minutes, allowing the lasagne sheets to soften.

Remove the lid and continue to simmer, uncovered, for 4–6 minutes until the lasagne sheets are almost cooked through and the liquid has reduced into a thick sauce.

Stir often using tongs to ensure the pasta remains separate and to prevent it sticking to the bottom of the pan. The sheets may break apart a little bit, which is fine. If there appears to be a lot of residual liquid in the pan, see note 2.

Add the chicken and parmesan to the pan. Stir them through carefully to avoid the pasta breaking too much. Remove from the heat and sprinkle over the mozzarella cheese.

Place the pan into the oven under the grill and cook for 3–5 minutes until golden brown on top.

Allow to stand for 5 minutes before serving (the longer it sits, the more the sauce will absorb into the pasta sheets). Serve with fresh oregano or basil leaves, if using.