Preheat the oven to 180 C / Gas 4. Grease a baking tray.
Scoop the flesh out of the aubergines and place into a mixing bowl. Place the aubergine shells onto the prepared baking tray.
Bake the shells for 10 minutes until they have softened a little. Remove from the oven and set aside.
Meanwhile, mash the aubergine flesh with a fork and set aside. In a frying pan over a medium heat, melt the butter and add the onion and garlic. Cook and stir for 4 to 5 minutes until soft and fragrant then add in the chopped peppers and mushrooms. Cook for a further 5 to 7 minutes. Add the Worcestershire sauce and hot sauce and mix well. Add the mashed aubergine, season well and cook for a further 6 minutes. Remove from the heat and allow to cool slightly before adding the breadcrumbs and egg, mix well.
Fill the par-baked aubergine shells with the stuffing mixture. Sprinkle the Parmesan on top and season well.
Bake in the preheated oven for 40 to 50 minutes until the aubergine is tender and the stuffing is firm and golden brown on top. Remove from the oven and serve.
Parmesan cheese is not truly vegetarian, as it contains animal rennet. To make this dish 100% vegetarian, omit the cheese or find a suitable vegetarian substitute made without animal rennet. In supermarkets look for the 'parmesan style hard cheeses' which are suitable for vegetarians.