1Heat the grapeseed oil in a large saucepan over medium heat. Cook and stir the shallots and 2 tablespoons chopped cilantro in the hot pan until the shallot has softened and turned translucent, about 4 minutes. Pour in the chicken stock, coconut milk, and agave nectar; bring to a simmer over medium-high heat. Once the broth reaches a simmer, strain through a mesh strainer into a clean saucepan; discard the shallot and cilantro.
2Return the broth to a simmer; stir in the mushrooms and broccoli and cook until the broccoli becomes tender, about 4 minutes. Add the chicken and cook until no longer pink, stirring constantly. Stir the curry paste, lime juice, and fish sauce in a small bowl to dissolve the curry paste; mix into the simmering soup.
3Ladle the soup into bowls and sprinkle with 1/2 cup cilantro, serrano peppers, green onions, and lime wedges to serve.