Ingredients:

• 2 tablespoons vegetable oil
• 1 tablespoon coarsely chopped garlic
• 2 stalks fresh lemongrass, trimmed and cut into 2-inch lengths
• 3 tablespoons curry powder
• ½  pounds whole bone-in chicken thighs or legs, or I pound boneless chicken breasts or thighs, cut into big bite-sized chunks
• 2 tablespoons fish sauce
• 1 teaspoon sugar
• ½  teaspoon salt
• 1 teaspoon dried red chili flakes or chili-garlic sauce
• 2 ¾  cups chicken broth or water
• 2 ½  cups unsweetened coconut milk (one 14-ounce can)
• 2  ½  cups chunks of peeled sweet potatoes or carrots

Directions:
In a large, deep saucepan, heat the oil over medium- high heat for 1 minute. Add the garlic, lemongrass, and toss well. Add the curry powder and cook, tossing often, until the herbs are fragrant, 1 to 2 minutes.
Add the chicken, spreading it out in one layer if you can, and cook for 1 minute. Toss well, and cook until the chicken changes color and begins to brown. Add the fish sauce, sugar, salt, and chili flakes and toss again. Add the broth and bring to a boil. Reduce the heat to maintain a lively simmer, and cook for so minutes, stirring now and then.
Add the coconut milk and sweet potatoes and simmer until the sweet potatoes are tender and the chicken is cooked, 10 to 15 minutes. Remove the lemongrass chunks, transfer the chicken and sauce to a serving bowl, and serve hot or warm.