Preheat oven to 400 degrees F. Line sheet pan with parchment paper and set aside.

Prepare fennel bulbs by cutting off stalks, fronds and root ends. Discard stalks and roots, and coarsely chop fronds to use as garnish. Cut fennel in half lengthwise then into wedges. (Note: To keep each wedge intact, cut through the inner core.)

In medium bowl, toss fennel wedges with olive oil, chili powder, cayenne, salt and pepper until evenly coated.

On prepared sheet pan, arrange seasoned fennel in single layer and roast 30 minutes or until fennel is brown and soft.

Flip fennel, sprinkle walnuts on top and continue roasting 15 minutes.

While fennel roasts, prepare citrus dressing. In small bowl whisk together orange zest, orange juice, olive oil, walnut oil, salt and pepper.

To serve, arrange roasted fennel and orange slices on large platter, garnish with toasted walnuts, chopped fennel fronds and citrus walnut dressing. Top with fresh black pepper.