This is a small labour of love but so worth it! It is also an easy way of using up the odd stick of celery or handful of mushrooms lurking in the fridge. You can always double up the ragu and use it for bolognaise sauce, cottage pie etc.
For the ragu
2 tbsp olive oil
400g beef mince
1 onion, roughly chopped
2 sticks celery, a handful button mushrooms,2 carrots diced (optional)
2 garlic cloves, crushed
1 tbsp chopped thyme
2 bay leaves
2 x 400g cans chopped tomatoes
For the white sauce
25 plain flour
salt and freshly ground black pepper
For the lasagne
6 fresh lasagne sheets
50g mature cheddar, grated
Preheat the oven to160C
For the ragu, heat a large frying pan until hot and add the oil. Cook the mince until browned all over. Remove from the heat and transfer to a plate. Add the onion, to the pan and cook for 10min, then add the celery, mushrooms, carrots and garlic and cook stirring, for another 10min. Return the meat to the pan and stir in the herbs, tomatoes and tomato ketchup. Bring to the boil then stir well, cover and simmer on the hob or in the oven for 1-½ hours, or until the beef is tender.
For the white sauce, melt the butter in a heavy based saucepan. When it is bubbling, add the flour and cook over the heat for one minute. Gradually whisk in the milk, whisking until thickened. Season well with salt and pepper.
For the lasagne, put one third of the meat sauce in the base of a 1-1.2litre shallow ovenproof dish. Spoon one third of the white sauce on top. Arrange one layer of lasagne sheets on top. Season. Spoon half of the remaining meat sauce on top and then half of the white sauce. Put another layer of lasagne sheets on top, then the remaining meat sauce and remaining white sauce. Sprinkle over the cheddar cheese.
Cook in the middle of a hot oven 200C for about 45 minutes- or until golden brown on top, bubbling around the edges and the pasta is soft.