To begin, prepare the barbeque sauce. In a pan, mix together tomato ketchup, English mustard, Worcestershire sauce, brown sugar, garlic powder, onion powder, red chilli flakes, black pepper powder, apple cider vinegar, and salt. Mix well.
Switch on the heat, bring to a boil, and let it simmer for a few minutes until it thickens. Remove and keep aside.
In a large bowl, take about a cup of shredded chicken. Add in about 3/4 cup of barbecue sauce. Mix well and keep aside for a few minutes so that the chicken soaks in the flavors.
To make the sandwich, butter the bread slices. Spread the BBQ Pulled Chicken generously over one of the slices. Add some cole slaw for the crunch and top it with the other slice.
Grill the sandwich until the bread is toasted. And slice into two.
The BBQ Pulled Chicken Sandwich is ready to serve. Serve with dips of your choice.