Preheat your oven to 400°F (200°C). Lightly oil a baking dish and set aside.
In a medium saucepan, bring the water to a boil. Gradually whisk in the polenta and salt, reduce the heat to low, and cook, stirring constantly, until the mixture thickens and the polenta is tender, about 15-20 minutes.
Spread the cooked polenta evenly into the prepared baking dish, then drizzle with olive oil. Place in the preheated oven to start baking.
While the polenta is baking, toss the cherry tomatoes with olive oil, garlic powder, dried oregano, and a pinch of salt and pepper. Spread them out on a baking sheet.
Place the tomatoes in the oven with the polenta and roast until they are blistered and bursting, about 20 minutes.
Remove both the polenta and the tomatoes from the oven. Arrange slices of mozzarella cheese over the polenta and return to the oven for another 5-10 minutes, or until the cheese is melted and bubbly.
Once the cheese is melted, top the polenta with the roasted tomatoes, sprinkle with fresh basil and grated Parmesan cheese.
Serve hot, allowing the flavors to meld together for a couple of minutes before digging in.