In a large bowl, season drumsticks with white vinegar, salt, black pepper, smoked paprika, chicken seasoning, onion and garlic.
Stir well until all the chicken is coated by the marinade.
Set in the fridge for at least 6 hours for the seasoning to be absorbed in the meat.
Pour stout in small saucepan with sugar and stir.
Boil for 2 minutes or until the mixture thickens slightly.
Pour reduced stout into BBQ sauce and mix thoroughly.
When ready to bake, bring chicken to room temperature as you preheat oven to 375 degrees F.
Dip each drumstick into the Stout BBQ sauce for even coating.
Return to the baking tray and bake for 30 minutes until the juices run clear when you cut into the meat. (TIP: To allow for better browning, baste the chicken a second time half way through cook time with more barbeque sauce)
Remove chicken from oven and let rest for about 5 minutes.