Preheat the oven to 200º C.
Spread the sweet potatoes, carrots and red peppers onto a greased baking sheet. Drizzle with 1 tablespoon olive oil and season with salt and black pepper.
Roast for 40-45 mins.
Sauté the onion in the remaining olive oil until softened. Add the garlic, oregano and rosemary and cook for a further 2 mins.
Stir in the pasta sauce and heat through.
Add the tuna and simmer over a medium heat for several minutes. Adjust the seasoning if necessary.
Arrange half the roast veg in an ovenproof baking dish.
Cover with the tuna sauce and top with the remaining vegetables.
Scatter over the breadcrumbs and Parmesan cheese.
Bake for 20 mins or until the crumbs are golden and the cheese melted.
Garnish with fresh basil and roughly chopped parsley.