Put shredded cabbage into large pot and add 1 cup water. Cover with lid, and "steam" until tender but not mushy, stirring occasionally.
Add 1 T oil and sprinkle with flour, about 2 T. Mix to combine well, and cook a minute or two. Season with salt and pepper. Add the cinnamon, vinegar and sugar. Stir to combine, then add ½ jar grape jelly. Stir well until jelly has melted and sauce is thick. Taste and adjust seasonings.