Begin by heating a large skillet over medium-high heat. Season your beef roast with salt and pepper, then sear it in the hot skillet for 4–5 minutes on each side until a rich brown crust forms, enhancing the flavor for your Slow Cooker Beef Manhattan. Once browned, transfer the roast to the slow cooker.

In the same skillet, reduce the heat to medium and add a touch of oil if needed. Sauté the diced onions and minced garlic for about 3–4 minutes, or until the onions turn translucent and fragrant. This step will add a depth of flavor to the broth. Once ready, layer the sautéed mixture over the beef in the slow cooker.

Carefully position the seared beef on the bottom of the slow cooker. Evenly distribute the sautéed onions and garlic on top of the beef, creating a flavorful foundation for your dish.

Pour your beef broth and red wine over the layered ingredients in the slow cooker. Incorporate the tomato paste and Worcestershire sauce, mixing gently to combine. Add fresh thyme and rosemary, along with a sprinkle of salt and pepper, ensuring even distribution.

Cover the slow cooker with its lid and set it to low for 8 hours or high for 4–5 hours. Check at the end of the cooking time; the beef should shred easily with a fork.

Once cooked, carefully remove the beef from the slow cooker and shred it using two forks, if desired. Return the shredded beef to the pot and stir into the savory broth for added moisture. Garnish with fresh parsley.