Heat the oil in a non-stick pan and fry the onions, ginger and garlic for 8-10 minutes, stirring typically, until softened and starting to paint. Add the spices and chilli flakes, stir briefly, then pour throughout the tomatoes with half a can of water and the honey. Blitz all of the issues throughout the pan with a hand blender until just about clear (or use a meals processor). Stir throughout the pepper and coriander stalks, cowl the pan and go away to simmer for 10 minutes. (The mixture will possible be very thick and splutter barely, so stir typically.)