Cook the pasta according to the package directions and drain, reserving about 250ml of the pasta water.

In a heavy based sauce pan or high sided skillet, heat the olive oil over medium heat until the oil shimmers. Add the smoked bacon lardons and cook for about 8-10 minutes, until the fat starts to render out and the lardons are turning golden. 

Add in the onion and garlic and about a teaspoon of salt. continue to cook until they’re both softened and fragrant. This should take about 5 minutes. Mix the tomato pure into the onions and garlic and let cook for about 2 minutes. Pour the passata or chopped tomatoes into the pan and bring to a simmer. Check for seasoning. If the sauce needs thinning out, pour in a spoonful or two of the reserved pasta water. Add it sparingly so as not to make the sauce too thin.

Toss the cooked spaghetti into the sauce to coat all the pasta. Divide between bowls and top with the grated Grana Padano and chopped parsley. Feel free to also top with lots of fresh ground black pepper.