Cook pasta according to package directions and set aside.
In a large pan, heat butter over medium-high heat.
Add beef to pan and then season with salt and pepper. Brown on all sides, about 5 minutes. Remove beef from pan and set aside.
Add 1 Tablespoon butter to pan.
Add onions and mushrooms and saute for 4 minutes or until at desired tenderness.
Add garlic and cook for another minute or so.
Stir in soy sauce.
Sprinkle flour over mixture and sir to coat.
Slowly whisk in beef broth to avoid lumps.
Add desired amount of thyme.
Bring mixture to a boil and cook until thickened (a few minutes).
Add beef back to pan and season with salt and pepper.
Cook for another minute.
Serve over noodles.