Preheat hob about medium heat. Put saucepan on the heat and put the butter in the saucepan until melted. Once melted, put in the vegetables (except for tomatoes and spinach) and the curry powder in the saucepan and cook until transparent.
Pour in the water and add the tomato paste, chopped tomatoes, coriander and flour until thick. Once thick, add the spinach and stir it in. Take off the heat to serve.