01 - 
                Season short ribs on all sides with salt and pepper.
              
              
              
                02 - 
                Heat oil in a large skillet over medium-high heat. Add seasoned ribs to the hot oil (bone side up first) and sear on each side for 1-2 minutes, until browned. The ribs will not be cooked through.
              
              
              
                03 - 
                Remove and transfer ribs to a large crockpot.
              
              
              
                04 - 
                To the same skillet, add onions, mushrooms, and tomato paste. Stir to coat the vegetables. Cook over medium heat until onions are tender, about 3-5 minutes. Add garlic and cook for one more minute.
              
              
              
                05 - 
                Increase the heat to high and pour in the beef broth, stirring often and scraping up the brown bits from the pan. Bring the mixture to a boil, then reduce the heat to medium. Simmer for 5 minutes, stirring and scraping the sides as needed.
              
              
              
                06 - 
                Pour the mixture over the ribs in the crockpot.
              
              
              
                07 - 
                Cover and cook on low for 7-8 hours or on high for 3-5 hours. The ribs are done cooking when they easily fall off the bone.
              
              
              
                08 - 
                Serve the braised short ribs over mashed potatoes.