Cook onions in 1 Tbsp butter or shortening in Dutch oven until tender-crisp; set aside. Brown roast in remaining butter or shortening in Dutch oven over medium heat 15 to 20 minutes or until browned on both sides.
Pierce entire surface of meat with fork.
Combine apple juice, catsup, salt, pepper, thyme, mustard and basil; add to meat. Top meat with reserved cooked onions; cover and cook slowly 2 1/2 hours or until almost tender.
Brush sweet potatoes with lemon juice for bright color; add to meat. Continue cooking, covere d, 30 to 40 minutes or until meat and potatoes are tender.
Place meat and potatoes on warm platter.
Sprinkle potatoes with chopped parsley or garnish with apple rings and parsley, if desired.
Serve gravy over sliced meat. NOTE: After apple juice mixture is added to browned meat, it may be marinated in the refrigerator until 3 to 4 hours before serving time; turn meat several times.
If Dutch oven is cast iron, transfer to a glass dish.
GRAVY: Skim excess fat from cooking liquid; add water if needed to make 1 1/2 cups.
Mix 1/2 cup water and 2 Tbsp Unbleached Flour; stir gradually into cooking liquid.
Heat to boiling; cook, stirring 3 to 5 minutes.
Season with salt and pepper, if desired.
Gravy may be served in Large Apple that has been scooped out, if desired.