• 1 piece (15 x 6 1/2 x 3/8-inch) oak grilling plank
• 1 cup(s) low-fat mayonnaise
• 1 teaspoons grated orange rind
• 2 tablespoon fresh orange juice
• 2 teaspoons chopped fresh chives
• 6 ounce bluefin tuna steaks (about 1 inch thick)cooking spray
• 1 teaspoons salt
• 2 tablespoon mixed peppercorns, crushed

Immerse and soak plank in water for 1 hour; drain.
Prepare grill, heating one side to medium and one side to high heat.

Combine mayonnaise, rind, juice, and chives; stir well with a whisk. Chill.

Lightly coat top of tuna with cooking spray. Sprinkle the tuna with salt; firmly press peppercorns into tuna.

Place plank on grill rack over high heat; grill 5 minutes or until lightly charred. Carefully turn plank over; move to medium heat. Place tuna on charred side of plank. Cover and grill 10 minutes or until desired degree of doneness. Serve tuna with orange mayonnaise.