In a large pot of salted water, parboil cannelloni. (Parboiling is partially cooking the noodles in boiling water; they will finish cooking when baked.)
Meanwhile, cook 2 cloves garlic and 2 shallots in 1 tablespoon olive oil in a medium saucepan over medium heat for 30 seconds. Pour in sherry, raise heat to high and reduce liquid by half. Stir in cream and reduce until there is about 350ml liquid. Remove from heat and season with salt and pepper to taste. Set cream sauce aside.
In a large frying pan, heat one tablespoon olive oil over medium heat. Cook onion, 3 shallots, 3 cloves garlic, mushrooms, courgette and aubergine in olive oil until all vegetables are tender. Transfer to a large bowl. Stir in red peppers, basil, oregano, ricotta and Parmesan cheese. Season to taste with salt and pepper. Set filling aside.
Preheat oven to 180 C / gas 4. Lightly grease one 20x30cm baking dish. Stuff vegetable/cheese filling into cannelloni. Place in prepared baking dish and cover with cream sauce.
Bake in preheated oven for 25 minutes.
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.