Cut chicken into chunks. Heat pan over medium heat. Add in oil and chicken and sauté for to 2 to 3 minutes. Salt slightly. The chicken won’t be cooked through, it’ll continue to cook in the soup later on.
In a pot, bring coconut milk and chicken broth to a barely simmer over medium heat. Whisk to break up milk.
Add in the chicken, mushrooms, ginger, fish sauce, lime juice, cayenne powder and lemon grass. Simmer until the chicken is done and the mushrooms are tender, 10 to 15 minutes. You may need to lower heat.
Sprinkle with green onion and fresh cilantro and serve steaming hot. I also love serving this over steamed brown rice!
*Lemongrass: First, peel the outer layers (they look like corn husks). Then with the back of your knife, hit the lemongrass. You'll make indents all along the stalk. Then, cut into quarters.* You won't eat the ginger/lemongrass, but whenever I get this in restaurants, they always leave the pieces in the soup!