Cut the potatoes into cubes and place in a large pot. Cover with cold, salted water and bring to a simmer over medium heat. Cook for 10-12 mins, or until just tender. Drain and leave to steam dry.
Meanwhile, add the ginger, garlic, 1 shallot (we’ll usethe other shallot later), tomato paste, olive oil and red curry paste to a blender/food processor. Separate the leaves and stems from the coriander and add the stems to the blender/food processor. Blend until you reach a puree consistency. Season to taste with salt and pepper.
Cut the tomatoes into cubes. Heat the olive oil in a large non-stick frying pan over a medium heat. Finely slice the other shallot and add to the pan. Fry for 5 minutes.
Add the tomato mixture and bring to a simmer, then carefully stir in the potatoes and chopped tomatoes. Season to taste. Gently simmer the Bombay potatoes for a few minutes until everything is warmed through, then serve with sour cream and coriander leaves.
