In a medium saucepan, place the ginger beer, Worcestershire sauce, tomato ketchup, apple cider vinegar, hoisin sauce, spice powder, orange juice, garlic, lime juice, onion powder, brown sugar, salt, honey and pepper. Bring to a simmer on low heat for 15 minutes or until thickened. Add the chicken and keep warm.
Sweet potato bacon baps:
1) Preheat the oven to 210C/Gas 7.
2) In a small skillet, caramelise the onion with the olive oil and caster sugar. In the bowl of a food processor, combine the plain flour, brown sugar, baking powder, bicarbonate of soda and salt and pulse to combine. Add the butter and pulse until it resembles coarse crumbs. Remove the contents of the food processor to a medium bowl. Fold in the rasher bacon and onion.
3) Combine the sweet potato puree and buttermilk. Pour into the dry ingredients to form a soft dough. Place the dough on a plain-floured surface and pat into 2 1/2cm thickness. Cut out the baps with a 5cm cutter and arrange them in a buttered skillet. Place into the preheated oven for 25 minutes or until golden brown.
Allow the bread to cool slightly before making the sandwiches. To do so, split each bap in half. Place a generous 1/2 cup of barbecue chicken on the bottom half of the bap and top with other half.