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

In a skillet, heat 2 tablespoons of olive oil over medium heat. Add sliced onions with salt and sauté for about 10 minutes until they soften and become translucent.

Add sugar to onions and continue to cook for 15-20 minutes until deep golden brown. This step creates the rich flavor.

In the last few minutes, stir in minced garlic and cook until fragrant, about 1-2 minutes.

Reduce heat to low, add drained pasta to the skillet with onions and garlic. Toss gently to combine.

Stir in reserved pasta water gradually until you reach desired sauce consistency.

Drizzle remaining olive oil and chilli oil over pasta, season with black pepper and toss to coat evenly.

Serve warm, garnished with Parmesan cheese and chopped parsley.