1. In a large pot or Dutch oven, heat 1 tablespoon of oil over medium-high heat. Add the chicken and cook until golden brown and cooked through, about 5-7 minutes.
2. Remove the chicken from the pot and set it aside.
3. Add the lemongrass, kaffir lime leaves, ginger, garlic, and onion to the same pot. Cook for another 3-4 minutes, stirring occasionally, until the onion is softened.
4. Return the chicken to the pot along with the chicken broth, coconut milk, fish sauce, palm sugar, turmeric powder, and lime juice. Bring the mixture to a boil, then reduce the heat to low and simmer for 30-35 minutes.
5. Remove from heat and let it cool down for a few minutes. Skim off any foam or oil that has accumulated on top of the soup.
6. Ladle the soup into bowls and garnish with fresh cilantro leaves and fried shallots or onion rings.