Preheat your oven to 180°C (350°F).

Wash and cut the tomatoes into equal-sized blocks. Peel the garlic and chop the onion.

Place the tomatoes, garlic, and onion in a baking dish. Drizzle with olive oil, making sure everything is coated. Sprinkle with sea salt to taste.

Add the fresh rosemary sprigs to the mixture.

Roast in the oven for 15-20 minutes, or until the tomatoes are softened and starting to caramelize

While the tomatoes are roasting, cook 500g of spaghetti in salted water for 11-13 minutes, or until al dente.

Once cooked, reserve 1/2 cup of the pasta water and drain the rest.

Once the tomatoes are roasted, remove them from the oven and add the fresh cream to the mixture.

Use a stick blender to blend everything until smooth and creamy.

Add the reserved pasta water to the sauce, then stir in the grated Parmesan cheese until incorporated.

Pour the creamy tomato sauce over the drained pasta and stir to combine.

If you're using chili flakes, sprinkle them in now and mix through (they really enhance the flavor, so I highly recommend them!).

Dish up your pasta and serve with extra Parmesan and a sprinkle of chili flakes, if desired.