Heat olive oil in a large pot over medium heat.
Add onion and garlic to the hot oil. Season with generous pinches of salt and pepper, to taste. Cook by stirring occasionally or until the onion becomes soft and translucent. Do this for 3-4 minutes.
Add mushrooms and ground beef. Continue cooking until the beef is nicely browned and the mushrooms have released their liquid, another 5-6 minutes.
Stir in the tomato paste and add bay leaf, oregano, and dried thyme. Season to taste with salt and pepper.
Pour in the wine to deglaze the pan and continue cooking until most of the wine evaporates, 5-6 minutes.
Pour in the crushed tomatoes and reduce heat to medium-low. Let the Bolognese simmer gently until nicely thickened. Do this for 25-30 minutes.
Meanwhile, bring a large pot of salted water to a boil. Cook the pappardelle according to package instructions or until it's al dente.
When finished cooking, drain pasta and keep warm. Melt butter. Add hot pasta into the hearty sauce and toss to coat. Top with gruyere, parmesan, and parsley.
Serve the Beef and Mushroom Bolognese over the buttered pappardelle. Garnish with additional cheese and parsley. Enjoy!