Heat oil in a large pot over medium heat. Add garlic and stir for 10 seconds. Add cayenne and chilli flakes. Cook for 1 minute, until garlic is light golden.
Add tomato, salt, and pepper. Rinse out the tomato cans with water and add to the pot.
Turn up heat to high, stir, then simmer on medium heat for 15 minutes. Taste at 10 min – if sour, add sugar.
In a large pot, boil water with 1 tbsp salt. Add pasta and cook per package directions.
Just before draining, stir well then scoop out 1 cup of water and set aside. Drain pasta.
Add pasta to the sauce with 1/2 cup reserved water. Toss well until pasta is coated, adding more water to loosen if needed.
Divide into bowls and serve immediately with parmesan and parsley, if using.
Notes
Nutrition information is an estimate, calculated automatically. Values vary with brands, substitutions and portion sizes.