2 cups green cabbage (thinly sliced, about 1/4 of a small head)
2 cups red cabbage (thinly sliced, about 1/4 of a small head)
1 large fennel bulb (trimmed, quartered, cored and cut crosswise into thin slices)
3/4 cup raisins
2 tablespoons fresh lemon juice
2 large crisp apples, such as Fuji or Granny Smith (unpeeled, cut into 1/4 x 1/4 x 1-1/2-inch sticks)
1/4 cup walnut oil
1 1/2 tablespoons cider vinegar
2 teaspoons agave syrup (or mild, runny honey)
  Salt and freshly ground black pepper
1/3 cup candied or spiced walnuts (optional)