Heat 2 tablespoons of olive oil in a large skillet over medium-low heat. Add 2 thinly sliced yellow onions with a pinch of salt. Cook for 25–30 minutes, stirring occasionally until golden brown and soft.

In a small saucepan, warm 1/4 cup of olive oil over low heat. Add 2 thinly sliced garlic cloves and sauté for about 2 minutes until fragrant. Stir in 1 teaspoon each of red chili flakes and paprika, cooking for another minute. Add 1 tablespoon of soy sauce and simmer gently for 5 minutes.

Bring a large pot of salted water to a boil. Add 8 ounces of pasta and cook until al dente according to package instructions, usually 8-10 minutes. Reserve 1 cup of pasta water before draining.

In the skillet with the caramelized onions, add the drained pasta. Pour over the prepared chili oil, mixing thoroughly to coat every noodle. If too dry, incorporate some reserved pasta water until desired consistency is achieved.

Divide into serving bowls. Sprinkle with grated Parmesan cheese, fresh basil or parsley, and extra chili flakes if desired. Serve immediately.