Start by bringing a large pot of salted water to a rolling boil over high heat. Add the pasta and cook until al dente, about 8-10 minutes. Reserve 1 cup of pasta water before draining.

While the pasta is cooking, heat 2 tablespoons of olive oil in a large skillet over medium heat. Add onions and a sprinkle of salt. Sauté for about 10 minutes until softened.

Sprinkle sugar over the onions and cook for an additional 15-20 minutes until deeply caramelized and golden brown.

In the last few minutes, add minced garlic to the skillet and cook for 1-2 minutes until fragrant.

Reduce heat to low and add the drained pasta to the skillet, tossing well to combine with onions and garlic. Gradually stir in reserved pasta water to adjust sauce consistency.

Drizzle the remaining olive oil and chilli oil over the pasta. Season with black pepper and toss to coat each strand.

Serve warm, garnished with Parmesan cheese and freshly chopped parsley.