Place beef in a slow cooker and season generously with salt and pepper on both sides.
Add garlic, thyme and rosemary. Then top with chopped tomatoes and onions.
Cover and set slow cooker on high for 4 to 8 hours or until you can easily shred beef with two forks. It may take longer depending on how tough the beef is but begin checking after 4 hours.
Shred the beef and stir thoroughly. Let it cook for another 30 to 60 minutes or until the water reduces to your taste.
Serve over rice, mashed potatoes or starch of choice with a side of vegetables or in tacos.
