BBQ Chicken Wings

Name: BBQ Chicken Wings
Prep time: 10 min
Cook time: 1 h 30 min
Total time: 1 h 40 min
Cuisine: American
Ingredients: 1 kg (2.2 lbs) chicken wings; 2 level tbsp aluminium-free baking powder (It has to be baking powder NOT baking soda - see further notes on baking powder below); ½ tsp salt (make sure it's regular table salt); ½ tsp pepper; 300 ml (1 1/4 cups) tomato ketchup; 4 tbsp white wine vinegar; 5 tbsp dark brown sugar; 2 tbsp black treacle or molasses; 3 tbsp honey; 2 tbsp vegetable oil; 1 tbsp Worcestershire Sauce; 1/2 tsp mustard powder ( - or 1 tsp English mustard); 1 1/2 tsp smoked paprika; 1/2 tsp black pepper