Season the beef short ribs: Generously season the short ribs with salt and black pepper on all sides to enhance flavor.

Sear the short ribs: Heat olive oil in a large skillet over medium-high heat. Once hot, place the short ribs in the skillet and sear each side for 1-2 minutes until nicely browned. This step locks in flavor and adds depth to the dish.

Prepare crock pot base: Lay the sliced onions at the bottom of the crock pot, then arrange the seared short ribs on top of the onions.

Mix and add liquids and herbs: In a bowl, combine minced garlic, dried rosemary, dried thyme, beef broth, Worcestershire sauce, yellow mustard, and tomato paste. Stir well until fully mixed. Pour this mixture over the meat in the crock pot.

Add bay leaves and slow cook: Place the bay leaves on top of the short ribs. Cover the crock pot and cook on low heat for 6-8 hours, until the meat is tender and easily pulls apart.

Make the gravy: Carefully remove the meat and set aside. Mix ¼ cup of the cooking liquid from the crock pot with the cornstarch in a small bowl to create a slurry. Gradually pour this slurry back into the crock pot while whisking to prevent lumps. Add the meat back into the crock pot and cook until the gravy thickens to desired consistency.

Serve: Serve the tender short ribs generously smothered in the rich gravy, ideally over a bed of creamy mashed potatoes for a hearty, satisfying meal.