Remove outer leaves of cabbage and discard. Cut head into quarters. Shred into thin slices using a mandoline. Trim onion and garlic, removing any sprouts.
In a large bowl, toss cabbage with onion, garlic, and parsley. Add vinaigrette. Transfer to 2 quart flat casserole. Splash with red wine vinegar. Place in refrigerator for a few hours or overnight.
Remove from refrigerator. Toss lightly. Place in preheated 350° oven for 30 minutes. Toss once or twice during cooking time. Let come to room temperature to serve. Taste and splash with more RWV for a little accent...your call....
MJ dishes it out:
This is also delicious uncooked. But, it stills needs to have an overnight in the refrigerator.
Marinated onions, which are a part of Xavier's vinaigrette, can be used instead of raw onions. This will reduce the amount of vinaigrette used.