Preheat the oven to 420°F / 220°C. Then place all the chopped cauliflower, broccoli, carrot, and zucchini in a ceramic baking dish.
Heat oil in a pan, add onion, and saute until well browned.
Add the tomatoes and basil, then simmer for 2-3 minutes until nicely softened and saucey.
Pour the mixture over the top of the vegetables, then use a spoon or spatula to mix the tomato into the vegetables so they are covered.
Make sure the vegetables are dispersed evenly and then cover with a sheet of foil and then cook for 40 minutes.
Remove the baking dish from the oven, top with the cheese and then put back in the oven uncovered. Bake for a further 10 minutes with the foil off so it goes nice and brown.
Eat hot or cold and serve beside some fish, chicken, or beef for a tasty, healthy meal.