Preheat the oven to 375°F (190°C).
Finely slice the onion and mince the garlic.
Heat the olive oil in a large skillet over medium heat. Add the onion and garlic and cook until softened, about 5 minutes.
Pour the canned diced tomatoes into the skillet and stir to combine. Bring the mixture to a simmer.
While the tomato mixture is simmering, slice the aubergine, bell pepper, zucchini and fresh tomatoes into 4-6 mm (approx.1/4 in) slices.
Use an oven dish and transfer in the tomato mixture or the pan, if it's oven proof.
Layer the sliced vegetables on top of the tomato mixture, and season with, the herbs, salt and pepper.
Bake in the preheated oven for 60 minutes or until the vegetables are browned and very tender.
Serve with your favorite protein. Enjoy!