Prepare the Marinade: In a large bowl, mix together 1 tbsp dry sherry, ¼ tsp black pepper, 1.5 tsp soy sauce, 1 tbsp minced garlic, and ½ tsp salt. Once combined, add the 8 chicken drumsticks to the bowl, ensuring they are well-coated in the marinade. For the best flavor, marinate for at least 10 minutes, but overnight is ideal.
Create the Batter: In another bowl, combine 1.25 cups tapioca starch, ½ tsp onion powder, 1 tsp garlic powder, 1.5 tsp curry powder, ½ tsp salt, ¼ tsp black pepper, and 1 tsp baking powder. Gradually whisk in ½ cup + 2 tbsp cold water, mixing until the batter is thick but runny.
Coat the Chicken: Remove the marinated chicken from the marinade and coat each piece in the batter thoroughly. Make sure every bit of the chicken is well-coated for the ultimate crunch.
Heat the Oil: In a large, deep pan, heat 4 cups of vegetable oil over medium heat until it reaches about 350°F. You can test the temperature by dipping a chopstick into the oil; if bubbles form around it, the oil is hot enough.
Fry the Chicken: Carefully place the coated chicken in the hot oil, frying in small batches (about 4 pieces at a time). Cook for about 10 minutes on each side, or until golden brown and cooked through. The internal temperature should reach 165°F.
Drain the Chicken: Once done, use a slotted spoon to remove the chicken from the oil and drain it on a wire rack or paper towel-lined sheet. This will help keep the chicken crispy.