Bring a large pot of salted water to a boil. Cook egg noodles according to package directions until al dente. Drain and set aside. Meanwhile, heat olive oil in a large skillet over medium-high heat. Add ground beef and cook until browned, crumbling with a spoon. Drain excess grease.

Reduce heat to medium, add butter to the skillet with the beef. Once melted, sprinkle in flour and seasonings. Cook for 1 minute, stirring constantly. Slowly whisk in beef broth until smooth. Bring to a simmer to thicken, then reduce heat to low and stir in the sour cream until combined.

Turn off the heat and add the cooked noodles to the skillet, folding gently to coat everything in the sauce. Pour the mixture into a 9x13 inch baking dish and spread evenly. Top with the shredded Gruyère and Provolone cheeses.

Preheat oven to 375°F (190°C). Top the cheese with the crispy fried onions. Bake for 20-25 minutes, until the sauce is bubbly and the topping is golden-brown. Let rest for 5-10 minutes before garnishing with fresh parsley and serving.