In a medium pot, heat the coconut oil over medium heat. Add the onion, garlic, chile, galangal or ginger, lemongrass, and red curry paste and cook, stirring frequently, for 5 minutes, or until onions are softened.
Add chicken broth and bring to a boil. Reduce head and simmer uncovered for 30 minutes.
Add in coconut cream or milk, chicken breast (or tofu or shrimp), and mushrooms. Simmer until chicken breast pieces are just cooked through, then add fish sauce, coconut aminos, and lime juice, plus more of each to taste.
Cook 2 minutes, then ladle into serving bowls and top with sliced green onions and fresh cilantro