Heat a large frying pan over medium-low heat. Add the pancetta and cook gently, stirring occasionally, for 8-10 mins or until the fat has rendered out and the pancetta is crisp and golden. Using a slotted spoon, transfer the pancetta to a plate.
Increase heat to medium. Add the breadcrumbs and stir for 3 mins or until golden. Remove the pan from heat and stir in the parsley. Season with salt and pepper. Transfer the breadcrumb mixture to a small bowl. Wipe out the pan with paper towel.
Place the pan over medium heat. Add the oil, garlic and chilli, if using, and cook, stirring occasionally, for 2 mins or until the garlic softens. Add the tomatoes and passata and cook for 5 mins or until the tomatoes soften. Stir in the pancetta.
Meanwhile, bring a large pot of salted water to a boil over high heat. Add the spaghetti and cook, stirring often to keep the strands separated, for 12 mins or until tender but still firm to the bite. Drain the pasta, reserving ½ cup (125ml) of the cooking liquid.
Add spaghetti to the warm sauce in the pan and toss gently to coat. If needed, add some of the reserved cooking liquid to loosen sauce. Season with salt and pepper.
Transfer pasta mixture to bowls. Sprinkle with parmesan, breadcrumb mixture and basil. Serve immediately.