Directions

1. Make the meat sauce: heat the oil in a large saucepan and gently cook the onions for 10 mins until golden. Add the garlic, herbs and bay, then cook 2 mins more. Heat a large frying pan. Crumble in a quarter of the beef, cook until brown, then add to the onions. Continue to fry the beef in batches and add to the onions until all the meat is used up. Tip the tomatoes and ketchup in with the onions and beef. Rinse the cans out with the red wine, if you have some, or with a little water, then add to the pan. Season and bring to a simmer. Gently cook for 30 mins until thick and saucy, then set aside.
2. Meanwhile, make the white sauce. Tip everything into a pan, season, then bring to a simmer, whisking continuously. Don't worry if it's lumpy - if you whisk enough the sauce will come together. Simmer for 5 mins, whisking, until smooth and thickened, then remove from the heat. If not using straight away, cover with cling film and set aside.
3. Make sure you divide everything up so that you can make two lasagnes. Place a thin layer of meat sauce in an ovenproof baking dish, drizzle with a little white sauce and scatter with a little mozzarella. Cover with a layer of lasagne sheets, then top with more of both sauces, more mozzarella and more lasagne sheets. Repeat once more, then cover the top layer of lasagne in just white sauce. Finally scatter over some Parmesan. The lasagnes can now be chilled in the fridge for a day ready to be cooked, or frozen for up to 3 months - see tips, below.
4. To cook, heat oven to 200C/180C fan/ gas 6. Cook for 35-40 mins until brown on the top and crisp around the edges. Leave to settle for 10 mins before cutting into squares and serving with a green salad and some garlic bread, if you like.