Steam the mussels in a pot with a tight fitting lid together with the garlic and few of the herbs stalks over a moderate fire until all mussels are open. Discard of any closed mussels, remove the rest from their shells and strain the remaining liquid. Mix the spaghetti with the caponata, tomato sauce, pepperoncino and herbs. Add the mussels and adjust consistency with the juice and Parmesan cheese. Grease an oven proof dish with the olive oil and line with the grilled aubergines. Fill in with the pasta and cover with the remaining aubergines. Bake in a moderate oven for 20minutes until set. Take out of the oven, allow cooling slightly and turning onto a serving plate.