How to Make It
Preheat oven to 350°F. In a mortar and pestle, sprinkle 1/2 teaspoon salt over garlic, ginger, and 1 tablespoon serrano chile. Pound and grind it to a relatively smooth paste, about 5 minutes; set aside.
Heat 2 tablespoons coconut oil in a deep 12-inch cast-iron skillet over medium-high just until smoke rises from skillet. While pan heats, season chicken evenly with 2 teaspoons salt and 1/2 teaspoon pepper. Add chicken to pan, skin side down, and cook, undisturbed, until deeply browned, 7 to 10 minutes. Transfer chicken to a plate, skin side up.
Reduce heat to medium-low. Add onion; cook, stirring occasionally and scraping up browned bits from bottom of pan with a wooden spoon, until onion is softened, 3 to 4 minutes. Stir in garlic mixture, and cook, stirring constantly, until slightly softened and fragrant, about 2 minutes. Add remaining 1 tablespoon coconut oil, and stir in turmeric, coriander, cumin, cardamom, and remaining 1/4 teaspoon black pepper; cook, stirring constantly, until spice mixture is fragrant, about 1 minute.
Add rice and collard greens, and cook, stirring constantly, until rice is coated in spice mixture and greens are slightly wilted, about 2 minutes. Stir in coconut milk, stock, and remaining 1/2 teaspoon salt until rice mixture is distributed evenly. Nestle chicken into rice mixture, skin side up, and bring to a simmer over medium-high. Simmer 3 minutes, cover pan, and transfer to preheated oven. Bake 10 minutes. Remove pan from oven. Lift up chicken to stir rice underneath; cover and return chicken to oven. Bake at 350°F until liquid is absorbed, about 10 minutes. Uncover pan, and bake until chicken and rice are cooked through, about 10 minutes.
Top with fresh cilantro and mint leaves, toasted flaked coconut, and remaining 1 tablespoon serrano slices. Serve with lime wedges.