01 - 
                Thinly slice the red onion and finely chop the garlic cloves.
              
              
              
                02 - 
                Bring a large pot of water to a rolling boil, add 2 teaspoons of salt, and cook the spaghetti until al dente according to package directions. Reserve 240 ml of pasta water before draining.
              
              
              
                03 - 
                Heat olive oil in a wide pan over medium heat. Add the sliced onions and sauté for 6–7 minutes, stirring regularly, until they become golden and caramelized.
              
              
              
                04 - 
                Add the finely chopped garlic to the pan and cook for 1–2 minutes, stirring until fragrant. Pour in the chili oil and mix to combine.
              
              
              
                05 - 
                Reduce heat to low. Add the heavy cream, Italian seasoning, and salt to taste. If the mixture is too thick, add a splash of reserved pasta water for desired consistency.
              
              
              
                06 - 
                Toss the drained pasta into the pan and combine thoroughly with the cream sauce, ensuring each strand is well coated.
              
              
              
                07 - 
                Serve immediately, garnished with freshly grated Parmesan cheese and chopped parsley if desired.