Heat 1½ tablespoons of neutral oil in a large pot over medium heat. Cook 2 large sliced yellow onions, stirring occasionally, for about 5 minutes, until soft and translucent.
Stir in 2 minced garlic cloves and 1 teaspoon of grated ginger. Add 680g of boneless chicken thighs, cut into bite-size pieces, and cook until no longer pink outside.
Add 4 cups of chicken stock, ½ grated apple, 1 tablespoon of honey, 1 tablespoon of soy sauce, and 1 tablespoon of ketchup.
Add 2 carrots and 3 Yukon Gold potatoes, cut into bite-size pieces. Bring to a boil, then simmer until the potatoes are tender when pierced with a skewer.
Turn off the heat. Dissolve 200g of Japanese curry roux in a ladleful of the liquid and stir it back in. Simmer uncovered over medium-low heat for 5-10 minutes, until thickened.
