drizzle each sheet with 4 1/2 teaspoons oil. season each with 1/2 teaspoon salt and a pinch of pepper; toss to combine. bake until cooked through, about 30 minutes. preheat grill to medium-high (if you are using a charcoal grill, coals are ready when you can hold your hand 5 inches above grill for just 3 to 4 seconds).