Prep and Sear Meat: Season meat with salt and pepper, generously, on all sides. Heat a large skillet over medium-high heat. Once the skillet is hot, add the oil. Once the oil is hot, add the meat. Sear on medium-high heat for a few minutes on each side, until all sides are well browned. Add to slow cooker: Lightly grease a slow cooker with non-stick cooking spray. Place meat in the bottom of the slow cooker. Mix sauce: Stir together the cream of soup mixture and dry onion soup seasoning in a bowl. Pour mixture over the meat in the slow cooker.  Slow Cook: Cover and cook on LOW for 8-10 hours. Check to see if the roast is done by poking it with a fork; it should shred easily. If it's tough, cook longer. If adding veggies, add them 1.5 - 2 hours before the timer is up.