Start by browning the ground beef in a large skillet over medium heat. Break it up as it cooks, and season it with a little salt and pepper. Once it’s cooked through, drain any excess grease and set the beef aside. I always find that cooking the beef first saves me time and ensures the flavors develop nicely.

In the same skillet, add a drizzle of olive oil and sauté the sliced onions. Let them cook slowly over medium heat until they’re golden brown and caramelized—this step is key for that deep French onion flavor. Trust me, it’s worth the extra few minutes! If you’re in a pinch, you can cook the onions on higher heat, but I really recommend giving them the time they deserve.

Once the onions are caramelized, add the beef broth, Worcestershire sauce, garlic powder, and thyme to the skillet. Stir well, scraping up any browned bits from the bottom of the pan. Let it simmer for about 5 minutes to let the flavors meld together. The aroma alone will have your mouth watering!

In a large mixing bowl, combine the cooked egg noodles, ground beef, and onion mixture. Stir until everything is well coated with the sauce. Transfer the mixture to a greased 9x13-inch baking dish. This step is where it all starts coming together, and you can already see how amazing it’s going to be.

Sprinkle the shredded mozzarella and Swiss cheese evenly over the top of the casserole. This is where the magic happens—cheese makes everything better, right? If you have kids who love cheese as much as mine do, they’ll be peeking into the oven waiting for that cheesy goodness.

Mix the French-fried onions and Parmesan cheese together in a small bowl. Sprinkle this crunchy topping over the cheese layer. It’s the perfect finishing touch that adds texture and even more flavor.

Preheat your oven to 375°F (190°C). Bake the casserole for 20-25 minutes, or until the cheese is melted and bubbly, and the topping is golden brown. Your kitchen will smell absolutely amazing by now, and you’ll be counting down the minutes until it’s done.