Slice the small aubergines into 1½ cm rounds, if you are using large aubergines, slice crosswise into 2 or 3 pieces and cut into wedges so that each piece has some skin. This will help them stay together. Heat the oil in a small non-stick saucepan and add the spices from the spice packet, including the chilli if you like the heat. Once the seeds are popping, add the aubergines with a little seasoning. Stir well in the oil, turn the heat down, cover and cook until the aubergines are soft, around 15 minutes.
Add the sauce and spinach and bring to a boil. If the sauce still looks thick, add a splash of hot water. Bring back to the boil and serve.