Preheat oven to 425°F. Line a sheet pan and set a wire rack on top.
Pat wings very dry with paper towels. Toss with baking powder and oil until coated.
Stir Cajun seasoning, garlic powder, onion powder, paprika, salt, pepper, cayenne, and brown sugar together.
Sprinkle the spice blend over wings. Toss until every piece is evenly seasoned.
Arrange wings on the rack, skin side up, leaving space between pieces.
Bake 25 minutes. Flip and bake until deep golden and crisp, 15 to 20 minutes more.
Whisk melted butter, hot sauce, and lemon juice in a large bowl.
Toss hot wings in the butter mixture. Rest 5 minutes so the coating sets.
Shower with chopped parsley and serve immediately.