Fill a large saucepan with water, add a good pinch of salt and bring to the boil.
Add the fusilli and cook according to the packet instructions until al dente, about 10–12 minutes.
Before draining, reserve about 120 ml of the pasta cooking water, then drain and set the pasta aside.
Meanwhile, heat the olive oil in a large frying pan over a medium heat.
Add the onion and cook, stirring occasionally, until softened and translucent, about 5–7 minutes.
Stir in the garlic and red pepper flakes and cook for 1 minute until fragrant.
Pour in the chopped tomatoes and the vegetable stock, then stir to combine.
Add the oregano and season generously with salt and freshly ground black pepper.
Bring to a gentle simmer, reduce the heat to low, cover and cook for 15 minutes, adding reserved pasta water a splash at a time if the sauce gets too thick.
Remove from the heat and stir in the basil.
Add the cooked fusilli to the sauce and toss to coat, adding more reserved pasta water if needed to loosen the sauce.
Divide between bowls and sprinkle over the Parmesan cheese.
Serve immediately, with a simple green salad or crusty bread if you like.