Heat half the butter and oil in a
pan, add the aubergines and potato slices and cook for 30 minutes,
turning over once or twice.
Remove from the pan.
Heat the rest of the butter and
oil, add the onions, garlic and tomatoes, and cook for 10 minutes
without browning.
Add half the aubergines and
potatoes, mix and season to taste with salt and pepper.
To make the sauce, melt the butter
in a saucepan, add the flour and stir over the heat for 1-2 minutes,
then gradually blend in the milk.
Stir until a smooth sauce is
formed.
Remove from the heat, add
approximately 6 oz of the cheese and season with salt, pepper, mixed
spice or nutmeg and mustard.
Spoon half of the mixed vegetables
into a casserole, add half of the sauce and the remainder of the
mixed vegetables.
Top with a neat layer of
aubergines and potatoes, then the rest of the sauce.
Cover the casserole with a lid or
foil; make sure this does not touch the sauce.
Bake for 75 minutes in a preheated
oven, 325F, gas mark 3.
Remove the lid, add the remaining
cheese, return to the oven, raising the heat slightly, and cook for
a further 10 minutes, or until the cheese topping has melted.