Position oven racks in the lowest and highest slots.
Preheat oven to 250°F / 120°C.
Line a large rimmed baking sheet with parchment paper.
Pat the chicken wings completely dry with paper towels.
In a large resealable bag, combine the baking powder, salt, paprika, optional cayenne, and black pepper.
Add the wings, seal the bag, and shake until they are evenly coated.
Spread the wings in a single layer on the prepared baking sheet, leaving space between each wing.
Bake on the lower rack for 30 minutes.
Move the baking sheet to the upper rack, increase the oven temperature to 425°F / 220°C, and bake for another 45 minutes, or until the skin is golden brown and crispy.
Serve immediately.
Place the wings on a wire rack set inside the baking sheet. This allows hot air to circulate underneath, ensuring the entire wing gets crispy and preventing a soggy bottom.
Do not substitute baking soda for baking powder. Baking powder is crucial for drawing moisture to the surface to create a blistered, crunchy texture; baking soda will leave a metallic taste.