1. Preheat oven to 190°C (Gas Mark 5).
2. Make up Bolognese sauce - see spaghetti Bolognese recipe.
3. Make the white (bechamel) sauce:
Melt the margarine in a medium saucepan over a medium heat.
Stir in the flour and cook the "roux" for 1 minute.
Gradually add the milk, stirring until fully combined with each addition.
When all the milk has been added stir continuously over a medium heat until the sauce begins to thicken.
Cook over a high heat until the sauce starts to boil, then reduce the heat and simmer gently for 5 minutes stirring continuously.
4. Spoon half of the Bolognese sauce into an ovenproof dish.
5. Add a single layer of the lasagne sheets on top.
6. Pour half of the white sauce over the lasagne sheets.
7. Repeat the process then finish off with grated cheese on top.
8. Bake in the oven for about 40 minutes.
Bolognese sauce (see recipe for spaghetti Bolognese)
For the white (bechamel) sauce:
40g (1½ oz) margarine (2 level tablespoons)
40g (1½ oz) plain white/wholemeal flour (2 level tablespoons)
450ml (¾ pint) semi-skimmed milk
110g (4oz) mature cheddar cheese