Preheat the oven to 400°F (200°C).
Prepare the cherry tomatoes by trimming and halving them.
Toss the halved tomatoes with olive oil, salt, and oregano.
Spread the tomatoes on a baking sheet and roast in the preheated oven for 20-25 minutes.
In a saucepan, bring the water or broth to a boil, adding salt.
Gradually whisk in the cornmeal, reducing heat to low immediately.
Cook the polenta, stirring regularly, for about 20-25 minutes until thick and creamy.
Stir in the Parmesan cheese and herbs into the polenta.
Transfer the polenta to a greased baking dish.
Once the tomatoes are roasted, spoon them generously over the polenta.
Return the dish to the oven and bake for an additional 15 minutes.
Allow the bake to cool slightly before serving, garnished with fresh basil.