Heat the oil in a large saucepan over medium low heat and add the onions. Saute the onions until they are golden brown and caramelized (about 30 minutes). Turn up the heat to high, add the chicken and brown. Add the carrots, and the water then bring to a boil. Skim off any foam or oil that accumulates at the surface then lower heat to medium and add the potatoes, pureed apple, salt and garam masala. Simmer for about 30 minutes or until you can pass a fork through the carrots and potatoes and the meat is tender. For the roux, melt the butter in a small saucepan over medium low heat. Add the flour and garam masala, stirring until you have a thick paste. Add the cayenne pepper and some fresh ground black pepper and incorporate into the roux. Add the ketchup and tonkatsu sauce and combine. Continue to cook until the paste starts crumbling. Remove from heat and set aside until the meat and veggies are ready. To make the curry, just laddle about 2 cups of liquid into the roux then whisk until it’s smooth. Pour this mixture back into the other pot and gently stir until thickened. Add the peas and heat through. Serve over rice or noodles. http://norecipes.com/karei-raisu-japanese-curry-rice/