1.Discard top and bottom of eggplant; cut eggplant lengthways into ten 5mm slices. Discard rounded-skin-side slices. Place remaining eight slices in colander, sprinkle all over with salt; stand 10 minutes.
2.Rinse eggplant well under cold water; pat dry with absorbent paper. Cook eggplant and pumpkin, in batches, on heated oiled grill plate (or grill or barbecue) until tender.
3.Place sauce in medium saucepan; bring to a boil. Reduce heat; simmer, uncovered, 2 minutes.
4.Place four slices of the eggplant, in single layer, on oven tray; top with half of the spinach, half of the pumpkin and half of the onion. Spoon 2 tablespoons of the sauce over each then repeat layering process, using remaining spinach, pumpkin, onion and another 2 tablespoons of the sauce for each stack. Top stacks with remaining eggplant slices; pour over remaining sauce, sprinkle stacks with cheese and nuts. Place under hot grill until cheese browns lightly.
Weight the eggplant when draining to extract as much water as possible; otherwise, the liquid causes the eggplant to soften and lose its shape when cooked. This process is called disgorging.Note