Heat a large Dutch oven over medium heat. When hot, add vegetable oil. Brown onions for about 5 minutes
Turn up heat and add chicken. Cook for another 5 minutes.
Add in carrots. Pour in apple juice and water and allow liquid to come to a boil. Lower heat and simmer for 5 minutes. Skim off fat appearing on the surface.
Add potatoes and continue to simmer for another 20 minutes.
In the meantime, cook the roux. Melt butter in a small saucepan over medium heat. Stir in rice flour and allow it to cook until smooth, about 5 minutes.
Add curry powder, garam masala, and cayenne pepper. Give it a good stir.
Add Worcestershire sauce and tomato ketchup and continue to stir until well incorporated and paste starts crumbling. Remove and set aside.
When meat and vegetables are ready, ladle about 2 cups (480ml) of hot liquid from Dutch oven into the roux and stir until smooth. Pour mixture back into Dutch oven and gently stir until thickened.
Add green peas and continue to simmer for another 5 minutes. Turn off stove.