In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the thinly sliced onion and cook, stirring every 5-7 minutes, until golden brown and soft, approximately 25-30 minutes. In the last 5 minutes, add minced garlic.

For the chili oil, in a small saucepan, warm 3 tablespoons of olive oil over medium heat. Add sliced garlic; sauté until fragrant, about 1-2 minutes. Stir in red chili flakes and paprika; cook for another 2-3 minutes. Drizzle in soy sauce before removing from heat.

Bring a large pot of salted water to a boil, add 12 oz. of pasta, and cook until al dente, about 8-10 minutes. Reserve 1 cup of pasta water before draining.

Add drained pasta to the skillet with caramelized onions, mixing well. Drizzle with chili oil, tossing well; add reserved pasta water gradually if the mixture is dry.

Plate pasta, sprinkling with grated Parmesan and fresh herbs; add extra chili flakes if desired.