Skin breasts and cut in half. Brown slowly in casserole dish in half the oil. When brown on all sides remove from casserole and keep warm. Heat remaining oil or butter in the casserole, add onion, and gently cook until brown. Stir in curry powder and cook 3 minutes. Sprinkle in flour and cook 1 minute. Remove from heat and pour in stock. Add garlic, bring to boil, and simmer 20 minutes. Return chicken to casserole, cover, and cook for 45 minutes or until tender. Transfer chicken to a platter and keep warm. Strain sauce into a pan, add coconut milk and jelly or lemon juice and simmer 3 minutes. Stir in heavy cream and thicken if needed with arrowroot. Add peaches, heat, and pour over chicken on platter.