When I found that my Bangkok Chicken Man had returned to his village for the holidays, I staged a stakeout. I finally found him, and got his recipe, thanks to my Thai teacher/translator/stakeout companion Jumbo's mastery of flattery (and the fact that we ate seven pieces of this chicken).
• 2 kilograms chicken legs and thighs, skin on (wings also work well)
• 4 large coriander (cilantro) roots, very lightly scraped (try using your thumbnail) and chopped fine
• 10 coriander stems, chopped fine
• 3 teaspoons whole black peppercorns
• ½ teaspoon red pepper flakes
• 14 cloves garlic, medium size, chopped
• 2 teaspoons salt
• 2 Tablespoons fish sauce
• ¾ cup plus 2 tablespoons rice flour (important—gives it a crackling crunch)
• 150 milliliters chicken stock
First, finely chop the coriander roots and stems, and peel and roughly chop garlic.
Place coriander and peppercorns into a mortar and pestle and pound to a paste, then add garlic and cayenne pepper and salt, continuing to pound to a fine paste.
Stir in fish sauce and chicken stock and mix well. Then gradually incorporate the rice flour until you have a smooth, wet batter.
Marinate chicken in this batter for at least two hours (ideally overnight)
Take chicken out of the fridge and allow to reach room temperature before frying in oil at 350 to 375°F until just past golden brown. Allow chicken to cool on paper towels for a few minutes, then chop into pieces if you like, or serve whole.
Thai Sriracha sauce makes a nice little dipping sauce, but it's not necessary.