Cooking a venison shoulder roast in your slow cooker is one of the best ways to tenderize the meat. Since venison is lean, it's best to add some cooking liquid so that it cooks in a moist environment, preventing it from becoming dry or tough. As an added bonus, once you prepare the roast and get everything into the slow cooker, you can pretty much turn it on and go about your day.
Prepare the venison roast by trimming all of the visible fat and connective tissue from the outside of the roast, and patting it dry with paper towels. Fat and connective tissues tend to be the source of strong flavor. By trimming it off, you reduce the gaminess of your meat.
Season the venison shoulder. You can keep it simple by using salt, black pepper and some chopped fresh herbs such as thyme and sage. Alternatively, you can make a dry rub with bolder flavor by combining garlic and onion powder, brown sugar, cayenne pepper and dry mustard with salt and black pepper.
Place the roast in your slow cooker along with some cooking liquid. This liquid will help tenderize the venison shoulder as it slowly cooks. The liquid can be as simple as some stock, wine or beer. You could also make a sauce for your roast. For example, you could combine equal parts of ketchup, brown sugar and apple cider vinegar with some dried mustard and cayenne pepper to make a zesty, barbecue-inspired sauce.
Cook the venison shoulder roast on high for 1 hour before reducing the slow cooker's heat to low, and cooking the roast for another 7 to 8 hours, or until the venison shoulder is fork-tender and a meat thermometer reads at least 160 degrees Fahrenheit.