1

To make the cheese sauce, whisk cornflour with ¼ cup (60ml) of milk in a saucepan to form a paste, then stir in the remaining milk. Cook over medium heat, whisking constantly until sauce boils and slightly thickens. Remove from heat, whisk in ricotta until combined, then stir in rind and season with salt and pepper. Set aside.

2

Lightly spray a large non-stick frying pan with oil and heat over medium-high heat. Cook chicken in batches, turning occasionally, until browned and cooked through. Transfer to a large bowl. Add leeks and 2 tablespoons water to same pan, reduce heat and cook, stirring, for about 10 minutes or until soft. Transfer to the bowl with chicken. Stir in tarragon and season with salt and pepper.

3

Lightly spray the pan again with oil. Add mushrooms, cook, stirring for about 5 minutes or until soft. Add garlic and spinach, increase heat and cook for a further 3 minutes or until spinach wilts and excess liquid evaporates. Season with salt and pepper and set aside.

4

To assemble lasagnes, divide one-third of the cheese sauce between 2 rectangular ovenproof dishes (about 28cm x 18cm), spreading evenly. Divide half the chicken mixture evenly over the sauce layer in dishes. Top each one with a layer of 3 lasagne sheets. Spread spinach mixture evenly over the lasagne sheets in each dish. Repeat layers of cheese sauce, chicken mixture and lasagne sheets, finishing with a layer of cheese sauce. Sprinkle with parmesan.