Fry the onions in the oil until golden. Mix the curry powder, chilli powder, garlic and ginger with a little water to form a stiff paste. Move the onions to the side of the pan and stir fry the paste on a high heat for 2 minutes (add a little extra oil if needed). Turn down the heat and add the Turkey. Stir the tomato puree into the stock or water and pour over. Bring to a boil then simmer on a low heat for 20 minutes stirring occasionally. Top up water level if it dries out. Stir in garam massalla for the last minute and then season with salt and serve. Optionally you may like to stir in some sugar and/or cream.