Pour olive oil in to the frying pan and fry the mince until it starts to brown; season with a bit of salt and pepper.
Once the mince looks cooked add the jars of tomato sauce and leave to sit whilst you make the béchamel
Heat the milk in a sauce pan, add some salt and pepper, the butter and mustard. When it is almost boiling add the cornflour mix – keep stirring with a whisk and it should start to thicken up. If not, add a little more cornflour (pre-mixed with a small bit of milk to keep it smooth).
Once the sauce has thickened add in the grated cheese.
Pour a layer of the tomato and mince sauce into a lasagne dish, then dry lasagne sheets. Repeat to create 3 layers, then pour on the béchamel sauce for the top layer. (You don’t need to grate any cheese on top as it makes a nice crispy layer anyway).
Place in the oven for 30 mins. Remove from the oven and let it sit for 5 mins. Enjoy!