How to Make It
In a large saucepan, toast the coriander seeds and black peppercorns over moderate heat, shaking the pan, until they are fragrant, about 1 minute. Remove the saucepan from the heat and let the spices cool slightly. Add the water, palm sugar, fish sauce, garlic, 8 of the kaffir lime leaves and the 1/4 cup of salt to the saucepan and bring just to a simmer. Stir to dissolve the sugar and salt. Remove the pan from the heat and let the brine cool completely. Add the chicken to the brine, cover and refrigerate for 8 hours or overnight.
Set a wire rack on a large baking sheet. Remove the chicken from the brine and pat it dry with paper towels. Put the chicken on the rack and refrigerate it, uncovered, for 2 hours to dry out the skin.
Preheat the oven to 400°. In a food processor, pulse the coconut cream with the remaining 2 kaffir lime leaves until the mixture has green flakes. Rub the chicken all over with the coconut cream and let stand at room temperature for 45 minutes.
Season the chicken lightly with salt and pepper and roast for about 1 hour, until an instant-read thermometer inserted in the inner thigh registers 165°. Transfer the chicken to a board and let rest for 10 minutes, then carve the chicken and serve.
Kaffir lime leaves are widely used in Thai cooking because they're wonderfully aromatic. They are available at Asian markets and also on Amazon.com. Coconut cream is the thick, rich cream that rises to the surface of unsweetened coconut milk. Look for it at specialty food shops.