Heat the oven to 425°F and set a lightly oiled wire rack over a foil-lined pan.
Blot wings thoroughly and toss with baking powder, 1/2 teaspoon salt, garlic powder and pepper.
Arrange with space and bake 25 minutes. Turn and bake 18 to 25 minutes more until browned.
Check several thick pieces away from bone and continue until every checked wing reaches at least 165°F.
Warm Dijon, honey, whole-grain mustard, vinegar, butter and remaining salt for 2 to 3 minutes, whisking until glossy; do not boil hard.
Rest wings 5 minutes, toss with enough warm glaze to coat lightly and serve extra glaze separately.