Position racks in the upper and lower thirds of the oven; preheat to 450 degrees F. Brush 2 large baking dishes with vegetable oil. Pat the wings dry; sprinkle with 2 teaspoons salt and 1/2 teaspoon pepper. Spread in the dishes and bake, rotating halfway through, until golden, 40 to 45 minutes.
Meanwhile, mix the dijon mustard, honey, mustard powder and garlic in a bowl. Remove the wings from the oven and toss with the mustard mixture, then continue baking until glazed, 3 to 5 more minutes.