3 1/2 pounds chicken leg-and-thigh quarters
1/3 cup coarsely chopped cilantro stems or roots
1/4 cup coarsely chopped garlic
1/4 teaspoon plus 1/8 teaspoon salt
3/4 teaspoon ground white pepper
2 teaspoons light palm sugar or light brown sugar
5 tablespoons fish sauce
1/2 to 3/4 cup Thai Sweet Chile Sauce
Trim excess fat and skin from the chicken. Put into a baking dish or bowl. Set aside.
Use a mini food processor to grind the cilantro stems, garlic, salt, pepper, and sugar to a coarse texture. Add the fish sauce and pulse to emulsify. Taste and season with salt, pepper, or sugar to create a marinade with a slightly intense savory-sweet bite.
Pour the marinade over the chicken. Use your hands to massage it into the chicken, making sure you get some between the skin and flesh too. Cover and set aside for 1 hour. Or, refrigerate for several hours, letting the chicken sit out for 45 minutes before grilling.
Preheat a gas grill to medium or prepare a charcoal fire to medium heat. Grill the chicken for 25 to 35 minutes, turning occasionally, until cooked through. Transfer to a platter. Brush on the sweet chile sauce or serve it on the side for guests to help themselves.