Bring first 9 ingredients to a boil in a large Dutch oven; reduce heat, and simmer 15 minutes. Add prawns, and cook 8 to 10 minutes or just until prawns turn pink. Drain, reserving stock. Cool prawns over ice. Cool stock. Return prawns to stock; cover and chill 2 hours.
Peel prawns, leaving tails on and reserving 6 heads. Toss Winter Cabbage Salad with Apple Cider Vinaigrette; chill 1 hour. Mound salad evenly on plates. Arrange prawns around salad. Serve with remaining vinaigrette. Garnish, if desired.
*18 jumbo shrimp may be substituted for prawns.