1-Pound chicken thighs or breasts to approximately ½-inch thickness.

2-Mix buttermilk, fish sauce, soy sauce, smashed garlic, and grated ginger to create the marinade.

3-Marinate the chicken in this mixture for at least one hour or preferably overnight.

4-In a bowl, combine 1½ cups all-purpose flour, ½ cup cornstarch, 1 tablespoon Thai curry powder, 1 teaspoon salt, and ½ teaspoon white pepper.

5-Dredge the marinated chicken directly into the flour mixture, pressing firmly to ensure the coating adheres well and do not shake off excess.

6-Heat vegetable oil to about 350°F (175°C) for frying; verify by dropping some flour into the oil, if it sizzles immediately, it is ready.

7-Fry chicken pieces without overcrowding the pan until golden and crispy, about 4 to 5 minutes per side. Adjust heat as needed to prevent burning.

8-Drain fried chicken on a rack to maintain crispiness.

9-Lightly toast the buns.

10-Assemble the sandwich by spreading spicy mayo on the bun, then adding lettuce, cucumber slices, chicken, onions, and cilantro as desired.

11-Serve the sandwich immediately to enjoy optimal texture.