Preheat the oven to 250°F / 120°C. Pat 2kg of chicken wing flats and drumettes dry with paper towels.
Toss the wings with 5 teaspoons of aluminum-free baking powder and ¾ teaspoon of kosher salt. Spread them out on a large baking sheet.
Bake for 30 minutes. Increase the oven to 425°F / 220°C and bake for 40-50 minutes more, rotating the baking sheet halfway, until dark golden brown and very crispy.
For the sauce, mix 4 tablespoons of melted unsalted butter, ½ cup of cayenne pepper hot sauce, 1 tablespoon of packed brown sugar, and ¼ teaspoon of kosher salt in a large bowl. Toss the hot wings in the sauce.
