In a large skillet, saute onion in butter until clear (3-4 minutes) over medium heat.
Add and browned beef (6-8 minutes).
Add 2 cups of broth, bay leaves, thyme, salt and pepper.
Bring to a boil. Reduce heat, cover, and simmer for 20-30 minutes, adding in the last cup of broth as needed.
Mix the cornstarch into the water. Stir this into skillet until thickened (+/-10 minutes).
Remove bay leaves.
In a separate pot, cook noodles in salt water as directed on the package.
Serve beef mixture over noodles.