Step 1

Toss the chopped lemongrass into a food processor. Process until it turns into a "fine, fluffy mass," scraping the sides with a spoon occasionally, about three minutes. Add the ginger, and pulse until it is chopped finely. Then add the onion. Process, scraping the sides with a spoon occasionally, until it is a paste.

Step 2

Pour the oil into a large saucepan set over medium heat. When shimmering, add the lemongrass paste. Cook, stirring often with a wooden spoon, until very fragrant, about two minutes. Add the curry powder and red chiles flakes, stir well, and cook for a minute. Add the salt, pepper, and coconut milk. Stir well with the wooden spoon, and then add the chicken pieces. If the liquid does not cover the pieces add a little bit of water to do so. Once liquid starts to boil, reduce heat to maintain a slow simmer. Cook, uncovered, for 20 minutes.

Step 3

Add the potatoes, stir well, and turn heat up again to bring to a strong simmer. Then reduce heat to maintain a bare simmer, and cook until the potatoes are tender, 15 to 20 minutes. When done, turn off the heat, cover the saucepan, and let rest for as long as you can stand it. (The recipe advocates 30 minutes, but I dug in after five.)

Step 4

Serve the dish with the lime wedges, cilantro, and white rice.