Place the shredded cabbage into a large glass baking dish or other glass dish. Do not use metal or plastic. Sprinkle with 1/2 cup of white sugar and the salt.
In a separate microwave safe bowl, combine the remaining sugar, oil, vinegar, mustard, celery seed and pepper. Stir to blend in the sugar, then heat until boiling in the microwave, about 3 minutes. Immediately, but carefully pour the boiling mixture over the cabbage. Toss with a wooden or plastic utensil to evenly coat the cabbage.
Let stand out on the counter for several hours, stirring occasionally. Cover and refrigerate. Toss before serving, and serve with a slotted spoon.