Caponata with cheesy polenta

Name: Caponata with cheesy polenta
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Cuisine: Italian
Ingredients: 1-2 tbsp olive oil; 1 red onion cut into thin wedges; 1 courgette cut into rounds; 1 aubergine cut into chunks; 2 garlic cloves crushed; 2 tsp dried oregano; ¼ tsp chilli flakes; 400g can chopped tomatoes; 30g pitted green olives halved; ½ tbsp capers drained and rinsed; ½ small bunch of basil finely chopped, plus extra to serve; 100g instant polenta; a little milk to loosen (optional); 40g parmesan or vegetarian Italian-style hard cheese, grated