Preparation Steps

• Cook pasta according to package directions. Drain and set aside.
• In a large skillet, melt butter over medium heat. Add sliced onions and cook, stirring occasionally, until softened and caramelized, about 15-20 minutes.
• Add minced garlic to the skillet and cook for 1 minute more until fragrant.
• Pour in beef broth and bring to a simmer, scraping up any browned bits from the bottom of the skillet.
• Stir in heavy cream, Gruyere cheese, and Parmesan cheese. Cook until the cheese is melted and the sauce is thickened.
• Season with salt and black pepper to taste.
• Add the cooked pasta to the skillet with the sauce and toss to combine. Serve immediately.