Start by adding the beef broth, tomato sauce, wine, salt, pepper, rosemary, thyme, and Worcestershire sauce to the slow cooker. Stir until combined.On the stove-top, place a skillet over medium-high heat, when the pan is hot, add enough cooking oil to coat the bottom of the pan. Brown the Brisket on both sides.Add the brisket into the sauce in the slow cooker.Sprinkle over the onions, and carrots.Cover and cook on HIGH for 5 hours. Add one more hour if you want the meat to shred, not slice.When the cooking time is done. Remove the brisket on to a cutting board, slice or shred. Before adding the meat back to the slow cooker, degrease the sauce. I do this by laying paper towels on the top of the sauce, then quickly pulling up. Discard paper towels, add the meat back to the sauce.Serve the beef, carrots and sauce over mashed potatoes.