Follow the steps in order for the best result.
In a bowl, thoroughly combine the buttermilk and garlic powder. Add the chicken pieces to this mixture, ensuring they are well coated. Allow the chicken to marinate for at least 2 hours, or even longer for a more intense flavor. During the marination process, remember to baste and turn the chicken pieces frequently to ensure even flavor penetration.
In a deep skillet, melt the butter (or oleo) over medium heat. Add the finely chopped onions and sauté for approximately 10 minutes, stirring regularly to prevent burning and ensure even cooking. The onions should become soft and translucent.
While the onions are sautéing, prepare the spice mixture. In a small bowl, combine the salt, ginger, curry powder, and cornstarch. Mix these ingredients thoroughly until well blended. Once the onions are ready, sprinkle this spice mixture evenly over them in the skillet, stirring continuously to ensure the spices are well incorporated and fragrant.
Remove the chicken pieces from the buttermilk marinade, reserving the buttermilk for later use. Place the chicken pieces in the same skillet with the spiced onions. Cook the chicken until it is lightly browned on all sides, turning as needed to ensure even browning. Once browned, pour the reserved buttermilk marinade over the chicken and onions.
Cover the skillet tightly with a lid. Reduce the heat to low and allow the chicken to simmer gently for approximately 1 1/2 hours, or until the chicken is tender and cooked through. During the cooking process, baste the chicken frequently with the sauce to keep it moist and flavorful. Check for doneness by piercing the thickest part of a chicken piece with a fork; the juices should run clear.