Oct 02, 2018 · Instant Pot 3-Ingredient Rump Roast–an easy beginner recipe for the Instant Pot. Beef pot roast is cooked until tender in the electric pressure cooker. If desired you can also make carrots and potatoes with the roast. Pin this recipe for later! Get the Slow Cooker 3-Ingredient Rump Roast recipe here. Jump to the recipe Put the roast in a slow cooker. Add the butter, au jus gravy mix, ranch dressing mix and pepperoncini peppers and juice. Add salt and pepper if you like and cook on low until tender, about 8 hours.