Preheat the oven to 325º F. Roll meat lightly in flour. Melt butter in Dutch oven over medium heat. Add onion and cook until softened.
Add beef, and lightly brown. Raise the heat to medium-high high and add the wine. Scraping the brown bits, cook until wine reduces slightly.
Heat stock with bouillon cube for 1 1/2 minutes in the microwave. Add beef stock and mushrooms. Season with salt and pepper. Place in the oven for 1 1/2--2 hours, stirring once, until the meat is tender. Add additional broth if needed.
During the final 30 minutes, bring a salted pot of water to a boil. Cook pasta until al dente. Remove pot from the oven, stir in sour cream.fresh parsley. Serve over pasta with a sprinkle of fresh parsley.