In a large bowl or airtight container, combine chicken and marinade ingredients: chicken, minced garlic, grated ginger, soy sauce, mirin, and black pepper. Massage the marinade into the chicken until fully absorbed. Cover and marinate in the fridge for at least 30 minutes or up to overnight.

In a small bowl, whisk together the sauce ingredients: soy sauce, mirin, brown sugar, honey, water, rice vinegar, and sesame oil. Set aside.

In a large bowl, prepare dredge by combining potato starch, garlic powder, baking powder, onion powder, and black pepper. Drizzle in water, mixing to create crumbles.

To the marinated chicken, mix in egg and all-purpose flour until just combined. Dredge chicken in the dry mixture, ensuring it sticks, then let it rest for 10-15 minutes.

In a wok, heat enough oil to deep fry on medium-high heat. Add chicken in batches, stirring gently to prevent sticking. Cook for about 3-5 minutes until golden brown. Remove and drain on a wire rack or paper towel-lined plate.

Allow oil to reheat, then return chicken to the oil in batches, cooking for 1-2 minutes until slightly darker brown. Remove and drain again.

In a cleaned wok or large skillet on medium heat, add garlic and ginger, cooking until fragrant. Pour in the sauce and simmer for 3-5 minutes until thickened. Combine with chicken until fully coated, garnish with toasted sesame seeds if desired.