Heat oil in a large nonstick saucepan over medium-high heat. Add onion, and sauté 10 minutes or until browned, stirring frequently. Add the minced ginger, curry, cumin, cinnamon, and garlic; sauté 1 minute. Add flour, tomato paste, sugar, salt, and pepper; cook 1 minute, stirring constantly (mixture will have a thick, pasty consistency).
Gradually add chicken broth, scraping the pan to loosen browned bits, and bring to a boil. Add the cubed potato and diced apple, and bring mixture to a boil. Cover; reduce heat, and simmer 10 minutes. Add peas, and bring to a boil. Cover, reduce heat, and simmer 10 minutes or until peas and potatoes are tender. Add the chicken to pan, and simmer, uncovered, 6 minutes or until chicken is done. Remove from heat, and stir in the sour cream. Serve with rice.