Caramelized Onion-Tortellini Spinach Salad Recipe

In a large skillet over medium-low heat, cook onions in butter and oil for 5 minutes or until tender. Add brown sugar; cook over low heat for 20 minutes or until onions are golden brown, stirring frequently. Meanwhile, cook tortellini according to package directions. Add the vinegar, salt and pepper to onion mixture. Bring to a boil. Reduce heat; cook 1-2 minutes longer or until syrupy. Drain tortellini and rinse in cold water. In a large serving bowl, combine the tortellini, spinach and Parmesan cheese. Add onion mixture and toss to coat.