Fill a large cast iron pan with vegetable oil so it reaches 2” (5cm) up the pan. Heat the oil to 350°F (180ºC).
In a medium shallow bowl add the flour and season with salt and pepper. Whisk the buttermilk and egg together in another medium bowl. One piece at a time, dip chicken in the buttermilk mixture, then dredge in the flour.
Shake off any excess flour and fry in the oil, flipping once, until the chicken is golden brown on all sides, about 8 minutes.
Remove the chicken and allow to drain on a wire rack set over a paper towel-lined baking sheet.
For the Thai slaw:
In a medium bowl whisk together the oil, garlic, chilies, ginger, lime juice, rice vinegar and fish sauce.
Add the cabbage, red onion, green onion, basil and mint and toss to combine with the dressing.
For serving:
Spread mayo on the bottom of each potato roll. Top with a piece of chicken followed by a pile of the slaw. Close the sandwiches and serve immediately.
Notes
While I prefer juicy chicken thighs, chicken breasts can also be used. Pound them to an even thickness to ensure they cook evenly. For a lighter option, grill or bake the chicken instead of frying. You can also air fry chicken tenders or cutlets for an easy shortcut.