1. Begin by heating the olive oil and butter in a large skillet over medium heat.
2. Add the sliced onions, salt, and pepper to the skillet. Stir to coat the onions evenly with the oil and butter.
3. Cook the onions, stirring frequently, until they become soft and begin to caramelize. This process will take about 20-30 minutes. If the onions start to stick, you can add a splash of water or broth.
4. Sprinkle the sugar over the onions and continue to cook them until they are deeply caramelized and golden brown.
5. Add the minced garlic and cook for an additional 2-3 minutes until fragrant.
6. Pour in the chicken or vegetable broth, stirring to deglaze the pan and incorporate all the flavors. Simmer for 5 minutes, then remove from heat.
7. Meanwhile, cook your pasta according to the package instructions until al dente. Reserve a cup of pasta water before draining the pasta.
8. Toss the cooked pasta with the caramelized onion mixture in the skillet, adding a bit of reserved pasta water as needed to help the sauce coat the pasta.
9. Stir in the grated Parmesan cheese and garnish with fresh parsley before serving.
Variations & Tips
For a vegetarian twist, use vegetable broth and consider adding a variety of mushrooms to the caramelized onion mixture for added umami flavor. If you prefer a bit of heat, a pinch of red pepper flakes can be incorporated during the caramelization process. For a creamy version, you might add a splash of heavy cream or a dollop of crème fraîche just before serving. Additionally, swapping out the Parmesan for Pecorino Romano can give a different flavor profile to the dish.