Rub the chicken with the mustard and leave to the side.
In a bowl mix the flour, baking powder, dried spices with a big pinch of salt and pepper.
Drop each chicken drumstick in the spice mix and place on a roasting tray, drizzle over some oil and roast for 40 minutes until cooked through.
To make the sauce heat the olive oil in a pot over a medium heat, finely chop the onion throw it in with the oil and cook for 5 minutes until soft. Throw in the crushed garlic and cook for another few minutes. When the onions are soft and fragrant add the rest of the ingredients plus a big pinch of salt and pepper and simmer for 30 minutes stirring every 5-10 minutes, blend the sauce with a hand blender or in a food processor and let it cool.
Serve the chicken with your BBQ sauce.