Cut the head of red cabbage in half and remove the core. Cut each half in half again to make quarters. Thinly slice each quarter width-wise (they should be around ¼ inch thick at most).
Peel and slice the red onions as thin as possible (almost "shave" it with your knife).
Place the sliced cabbage and onions into a large bowl.
Sprinkle on Italian seasoning, salt and pepper. Drizzle with oil and vinegar.
Toss well until well combine and taste it. Add additional dressing or seasonings if needed until it tastes fantastic. Refrigerate until ready to serve.
