Cut the chicken into small pieces and add it to the food processor and process until its minced.

Add all the spices and mix well. Take a portion of the chicken mixture and shape into a thin patty. Place on a tray lined with baking paper. Make all the chicken patties and put them in the freezer for 30 minutes, or longer, if it's still hard to handle.

In a large bowl, whisk together flour, corn flour, baking powder, salt, black pepper, paprika, and garlic powder.

Coat each patty in the dry mixture and shake off any excess.

Then add the water to remaning flour mixture and whisk to create a wet batter. The consistency of this should be thin.

Dip the chicken patties in the wet batter and then place in the hot oil. Fry in batches until golden brown.

Transfer to a wire rack to let any oil drain out.

In a small bowl, combine mayonnaise with mustard until smooth and creamy. Set aside.

Butter the buns and toast them in a pan over medium heat.

Assemble the toasted buns with the lettuce at the bottom followed by the chicken patty. Spread mayo over the top bun and put it on the top.