Instructions

1. 1

   Heat the oil in a large heavy-based pan, add the leeks, and cook over a low heat, stirring frequently, for 5 minutes, or until starting to soften. Stir in the mushrooms and cook, stirring frequently, for 5 minutes, or until they release their juices. Add the chillies and garlic, and cook for 1 minute. Pour in the wine, raise the heat, and boil for 3 minutes while the alcohol evaporates.

   
   

2. 2

   Stir in the thyme, then add the flour and mix well. Add a little of the milk, mix well, then add the rest of the milk and cook for 5 minutes, stirring frequently. Add almost all the cheese (reserve some for the topping), remove from the heat, and combine well. Add the tomatoes and season well with salt and black pepper.

   
   

3. 3

   Put a 1cm ( 1 / 2 in) layer of the mixture in the bottom of a large ovenproof freezerproof dish, then cover evenly with a layer of the lasagne sheets. Pour in another layer of sauce and cover with lasagne. Repeat the process until all the sauce is used up – you need to finish with a layer of sauce. Top with the remaining cheese and the sliced tomatoes.

   
   

4. 4

   Leave to cool completely, then double-wrap the dish in cling film and freeze for up to 3 months. To serve, remove the cling film, top with tomato slices, and place the dish straight from the freezer in an oven preheated to 180°C (350°F/Gas 4) for 30–40 minutes, or until browning on top and piping hot.