Trim the beef roast of excess fat. Rinse and pat dry. Rub oil on the top of the roast, then sprinkle on ginger and pepper and insert whole cloves into the roast. Next, sear the pot roast on all sides in a hot pan with oil. Place apples and onions into a crock-pot/slow cooker. Add the pot roast and pour apple juice over the entire roast. Cover and cook on low for 10–12 hours or on high for about 5–6 hours. Remove roast from slow cooker. Place it aside but keep it warm. Strain the pot roast juices and pour them back into the slow cooker. Turn heat to high to reduce liquid and thicken it up. Make a smooth paste with flour and water, then add it to the slow cooker, stirring as you combine. Cover and cook until thickened. Pour over roast just before serving. Optional: Garnish with fresh apple slices. Contributed by: Jan Brenkus, Berwyn, Illinois.