For this marinade you will need:
1. Grate the garlic and the ginger*
2. In a pan, add the oil and fry the onions on a medium heat for 5 minutes, or until softened and starting to colour.
3. Add the grated garlic and ginger from Step 1* (and chillies if desired) together with the contents of the Spice Bag and a little water to avoid the spices sticking. Stir well and cook for 2 minutes.
4. Add the chopped tomatoes to the pan together with the lemon juice, chicken stock and season with salt and cook on a medium heat for 10–15 minutes.
5. Combine the leftover food into the pan and continue to cook until the curry has reduced to your desired consistency.
6. Remove the cardamoms and cinnamon stick and serve with the fresh coriander leaves if desired.