Preheat oven to 375 degrees F. Combine beef, breadcrumbs, egg, thyme, garlic, green onions and salt and pepper to taste in a bowl. Roll into 1-inch round balls and place on baking tray. Bake 20 to 25 minutes, or until cooked through. While this occurs, place stock and flour in a pot that will be large enough to add the meatballs to after cooking. Whisk until lump-free, and then place over medium-high heat and bring to a simmer. Once sauce thickens lower heat medium-low and whisk in sour cream and salt and pepper to taste. Add meatballs to sauce once cooked, draining away any fat beforehand. Cook noodles until tender, and then toss with butter and parsley. Serve meatballs on bed of noodles.