Season the beef cubes with salt, pepper, and garlic powder.
Heat butter and oil in a hot cast-iron skillet, then add the beef. Sear until the outside is golden brown.
Add the onions, mushrooms, and garlic to the pan, stirring for about 5 minutes.
Lightly season with salt and pepper.
Sprinkle flour over the mixture and stir until there's no visible fat left at the bottom of the pan.
Pour in the vegetable stock, whiskey, Worcestershire sauce, thyme, and bay leaves.
Simmer for 1 hour and 30 minutes until the beef is fork-tender.
Once the beef is tender, stir in the Alouette cheese, Parmesan, and sour cream, whisking until everything is melted.
After the cheese melts, add the pasta and spinach. Season with salt and pepper to taste. Toss the pasta until the spinach is wilted.