Preheat oven to 250°F. Line a large baking sheet with aluminum foil, place a baking rack on the sheet, and spray the rack with non-stick cooking spray. Set aside.
Pat the 4 lbs chicken wings dry with paper towels.
In a large bowl, combine 2 tablespoons baking powder and ½ teaspoon ground black pepper. Add the wings and toss until each piece is evenly and thoroughly coated.
Arrange the coated wings in a single layer on the prepared rack (do not overcrowd). Place the baking sheet on the lowest oven rack and bake at 250°F for 30 minutes.
After 30 minutes, increase the oven temperature to 425°F and move the baking sheet to the upper-middle rack. Bake for 15 minutes.
Carefully turn each wing over and bake an additional 15 minutes, until the wings are crisp and cooked through (internal temperature 165°F).
While the wings finish baking, make the sauce: in a medium saucepan combine ½ cup hot sauce, 2 tablespoons molasses, and 4 tablespoons butter. Heat over medium, stirring until the butter melts and the sauce comes to a simmer, then remove from heat.
Transfer the hot wings to a large bowl, pour the sauce over them, and toss until evenly coated.
Transfer the sauced wings to a serving platter and serve immediately.