Apples and fennel are a terrific duo, and this super-simple slaw gives starring roles to both in a crunchy, colorful side dish that's heart healthy and delicious, too. A simple dressing made with cider vinegar, agave, and walnut oil moistens the components and contributes a tart-sweet note to the slaw. Candied or spiced walnuts are delightful but optional. If you do add them to the salad, do so just before serving so they don't lose their crunch.
Place the cabbage, fennel, and raisins in a large bowl. Place the lemon juice in another small bowl and add the apples, tossing to coat them with the juice (so they don’t turn brown). Set the apples and juice aside while you make the dressing.
Combine the walnut oil, vinegar, and agave in a small glass jar and seal tightly with a lid. Shake vigorously to combine. Add the apples to the cabbage mixture (discard any excess lemon juice) and toss to combine. Add all of the dressing and toss again to coat the slaw. Season the slaw with salt and pepper to taste.
The slaw can be refrigerated, covered, for up to 4 hours before serving. If you’re using the walnuts, garnish the slaw just before serving.