Cover the potato wedges with cold water for 20 minutes while the oven heats to 450°F with 2 rimmed sheet pans inside.
Drain the potatoes and dry them thoroughly between clean kitchen towels.
Toss the dry wedges with cornstarch first, then add the oil, salt, paprika, garlic powder and pepper.
Arrange the wedges cut side down in single layers on the hot pans, leaving space between pieces.
Bake for 20 minutes, flip each wedge and rotate the pans from top to bottom.
Bake for 15 to 20 minutes more until the broad sides are deeply browned and the centers are fluffy.
Let the fries stand on the pans for 2 minutes before serving so their crusts set.