Finely chop the onions, and mince the garlic. Chop the basil leaves.
Slice the chorizo.
In a large casserole pot or saucepan heat the olive oil. Add the chorizo and fry for about 3-4 minutes until crispy. Use a slotted spoon to scoop out and set aside, leaving the oil in the pan.
Add the chopped onion and cook on a medium heat for 10 minutes or until softened and translucent.
Add the garlic and chilli and cook for 1 minute. Stir in the tomatoes as well as the tomato puree, red wine vinegar and sugar. Bring the liquid to the boil, reduce to a simmer, loosely cover and cook gently over a low-medium heat for 45 minutes or until the sauce has reduced by a third and become much thicker in texture. Stir regularly to prevent the sauce catching on the base of the pan.
Stir through the basil and season to taste.
When your sauce is almost finished reducing, bring a large pan of salted water to the boil. Add the gnocchi and cook for around 3-4 minutes or until they begin to bob gently to the surface. Drain and toss with the tomato sauce.
Spoon the gnocchi to bowls and top with the crispy chorizo, grated Parmesan cheese and some more fresh basil leaves.