Prep the Meat. Start by trimming the excess fat off and cutting the beef into 1 ½ inch cubes. Season the meat with salt and black pepper.
Heat up vegetable oil in a heavy bottom large skillet over medium-high heat. Sear the beef chunks until well golden brown (about 4-5 minutes on both sides for a 1-2 inch chunk) Don’t overcrowd the pan, you’ll need to do this in batches, carefully cleaning the surface of the pan with a paper towel if necessary and adding more oil before the next batch. Don’t change the heat temperature and don’t overcook the beef.
Transfer the seared chunks into 4.5 quart slow cooker along with the browned bits form the pan.
Add the veggies (potato, carrot, mushrooms, onion). Sprinkle with spices.
In a small bowl or measuring cup mix beef broth, tomato sauce and Worcestershire sauce. Pour in the slow cooker and add 2 bay leaves.
Cook on LOW for 8 hours or HIGH 4 hours. After that taste for seasoning and add more salt/pepper if necessary.
Thicken the stew: Take out 2 cups of broth liquid from the slow cooker and add ½ cup of all purpose flour in batches, whisk well until combined before adding the flour each time. If any lumps occur, carefully remove them with a spoon. There should be no lumps in the end. Pour in the slurry back into the slow cooker. Gently stir to combine. Top with green beans and cook on HIGH for another 15 minutes or LOW for 30 minutes. Taste for seasoning again.
Serve as it is or with a portion of rice or simple green lettuce salad.