3 tablespoons curry powder, preferably Three Golden Bells brand
1/2 teaspoon salt, or to taste
2 pounds skinless chicken thighs
2 tablespoons vegetable oil
1 tablespoon chopped shallot
2 teaspoons minced garlic
2 teaspoons ground chili paste or dried chili flakes, or to taste
3 tablespoons fish sauce
1 tablespoon sugar
2 lemongrass stalks, cut into 3-inch pieces and bruised with the flat side of a knife
1 (1-inch) piece ginger, peeled, cut into 3 slices and bruised with the flat side of a knife
1 1/2 cups fresh chicken stock or store-bought low-sodium chicken broth
3 carrots, peeled, cut on the diagonal into 2/3-inch pieces
1 1/2 cups unsweetened coconut milk or cow's milk
1 yellow onion, cut into wedges
1 medium sweet potato (about 1 pound), peeled and cut into 1-inch cubes
1/2 cup Asian basil leaves, cut in half
8 sprigs cilantro, cut into 2-inch pieces
2 scallions, chopped