It's kind of rare to see curry cooking in a manga or anime that doesn't load it up with potatoes and carrots. But this recipe is still a bit too heavy on fat, isn't it?
I never put potato in curry, but I do put lots of other vegetables in, and as a result, usually I don't have to add water. How do you guys normally make curry?
If I were to make Butter Chicken, I would put tomato purée to after the juice and together with the spices make it into a very thick roux. Then I would just add cream to make it into a masala. I would also cook the chicken separately in an oven or a grill to give it a nice char.
I might at times put some stock into the roux inatead of just cream or yogurt, but never plain water. I also very rarely put any vegetables besides tomato into an Indian curry (onion, garlic, and ginger all count as aromatics), but with Japanese curry it's a different story.