When everything is nearly done, the tomatoes have turned to a pulp and coat all the vegetables in a thick sauce, add paprika and stir through. Then add the frozen spinach and close the lid. Leave again on low heat for another 5 minutes or until the spinach cubes melt and you can mix it through. (If using fresh wilted spinach, the spinach just needs to be added to the sauce for a minute or two just to heat through.