Sauce: Combine water, butter, cinnamon, vanilla, sweetener, and molasses in a saucepan. Bring to a boil and whisk in glucomannan. Remove from heat. Pour half of the sauce over the apples. Place pan of dumplings in the oven. Bake for 20 minutes, pour remaining sauce over apples. Cover with foil. Bake for an additional 25 minutes. Remove from oven. Spoon some of the sauce in pan over the dumplings. Cool. 6 servings.