Ingredients

  • 2/3 cup olive oil
  • 1 tablespoon Dijon mustard
  • 2 tablespoons chopped fresh thyme or 1 tablespoon dried
  • 1 teaspoon salt
  • 1 teaspoon ground black pepper
  • 2 pounds white-skinned potatoes (about 4 large), peeled, sliced 1/4 inch thick
  • 2 large red onions, halved, sliced 1/2 inch thick
  • Nonstick vegetable oil spray
  • Fresh thyme sprigs (optional)

Method

  • Combine oil, mustard, thyme, salt and pepper in large bowl.
  • Whisk to blend well.
  • (Can be prepared 6 hours ahead.
  • Cover and let stand at room temperature.)
  • Prepare barbecue (medium-high heat).
  • Add potatoes and onions to mustard oil.
  • Toss to coat.
  • Set six 18 x 9-inch sheets of heavy-duty aluminum foil on work surface.
  • Spray foil with nonstick vegetable oil spray.
  • Divide vegetables among foil sheets, placing in center of left half of each.
  • Sprinkle with salt and pepper.
  • Fold right half of foil over vegetables.
  • Fold edges of packages together to seal tightly.
  • Place packages on grill.
  • Grill until potatoes are tender and golden brown, turning occasionally, about 25 minutes.
  • Remove packages from grill.
  • Slit top of foil and fold back.
  • Garnish potatoes with thyme sprigs, if desired.