Heat half the oil in a large skillet. Add the beef and sprinkle with salt. Cook for 5-7 minutes or until browned. Place the beef in a crock-pot.
Add the onion, garlic, tomato pasta, Marsala wine, beef broth,pepper, thyme, mushrooms, carrots, and celery to the crock-pot. Mix everything to combine.
Stir in the flour to thicken.
Cover and cook on low for 8 hours.
Serve over top of mashed potatoes, rice, or noodles.