In a large/deep frying pan, add the extra-virgin olive oil and onion, along with the chilli flakes. Season with salt and saute for 5 minutes on a medium/low heat.
Next, add the tomato puree into the pan. Continue to fry on a low heat, stirring frequently. Meanwhile, add your pasta to heavily salted water setting your timer to 2 minutes, minus the packet time.
After the tomato puree has been frying for around 5 minutes, it should have darkened in colour. At this point, add the garlic to fry for a minute or two before adding two ladles of pasta water. Stir to combine.
Add the vodka into the pan and increase the heat to medium/high to cook off. Once the liquid is cooked off, reduce the heat to low.
Ensuring the pan isn't too hot, add the cream and parmesan. Stir to combine and when your pasta timer goes off, transfer the drained pasta into the pan (reserving the pasta water).
Loosen the sauce with another ladle of pasta water (or more if needed) as you stir the pasta into the vodka sauce. Cook until the pasta is perfectly al dente and incorporated in the sauce. Serve with a sprinkle of fresh parsley and an optional extra sprinkle of chilli flakes.