Slice the aubergines thinly, then place in
a colander, sprinkling each layer with salt. Cover with a plate, place
heavy weights on top and leave to degorge for 30 minutes. Meanwhile,
melt the butter in a saucepan. Add the flour and cook gently, stirring,
for 1-2 minutes. Remove from the heat and gradually blend in the milk.
Bring to the boil, stirring constantly, then simmer for 3 minutes until
thick and smooth. Add half of the cheese, the nutmeg and seasoning to
taste, stir well to mix, then remove from the heat.
Rinse the aurbergine slices under cold
running water, then pat dry with absorbent kitchen paper. Pour enough
oil into a heavy-based frying pan to cover the base. Heat until very
hot, then add a layer of aubergine slices. Fry over moderate heat until
golden brown on both sides, turning once. Remove with a slotted spoon
and drain on absorbent kitchen paper. Repeat with more oil and
aubergines. Arrange alternate layers of aubergines and tomatoes in a
oiled large gratin dish.
Sprinkle each layer with gratin, a little
salt and aplenty of pepper. Beat the eggs into the sauce, then pour
slowly into the dish. Sprinkle the remaining cheese evenly over the top.
Bake at 200C (400F) mark 6 for 20 minutes, or until golden brown and
bubbling. Serve hot.
Salting, or degorging, aubergines draws
out excess moisture and removes any bitter-tasting juices.