Bring a large pot of salted water to a boil, and cook the pasta according to the package instructions. Drain, and set aside.
16 ounces short pasta noodles
Melt the butter in a large pot over low heat. Add the olive oil and onions and cook for 15-20 minutes or until the onions have reduced significantly and caramelized. Don’t rush this process or the onions will burn.
2 tablespoons unsalted butter, 2 tablespoons olive oil, 2 large white onions
Stir in the mushrooms and cook for another 10 minutes or until the mushrooms have reduced significantly.
8 ounces baby portabella mushrooms
Pour in the beef broth, wine, thyme, Worcestershire sauce and salt and stir until combined. Bring the mixture to a simmer and allow it to simmer for 5 minutes.
1 cup beef broth, 1 cup dry white wine, 2 thyme sprigs, 1 teaspoon Worcestershire sauce, ½ teaspoon salt
Stir in the heavy cream and parmesan cheese until it is fully melted. Bring the mixture to a simmer again, and stir in the cooked pasta.
1 cup heavy cream, ½ cup parmesan cheese
Serve immediately with freshly minced thyme and toasted bread if desired.
See post for tips, variations, and storage options.