Heat the oil in a heavy bottomed pan
Add the onions, tej patta leaves and cinnamon to the pan and fry on a medium heat, stirring occasionally for 10 minutes or until just starting to turn brown.
turn the heat to the lowest you can and fry for another 30 minutes, stirring quite often until the onions have turned a deep brown colour.
Add the garlic and ginger and gently fry for another 20 seconds
Add the Kashmiri Chilli and stir in. Add the turmeric and stir in again before adding the curry masala. Fry for 20 seconds.
Add the tinned tomatoes and water and bring to a simmer.
Add the salt and cook for 20 minutes.
Add the fresh coriander, chillies and Garam Masala
continue to cook for another 10 - 20 minutes
Take the pan off the heat and let cool a little before fishing out the cassia and tej patta leaves
Now blend with an immersion blender, food processor or blender. If using the latter I would recommend to let it cool slightly first as hot steam tends to blow the lid off!
Use in any recipe that requires a Hotel Style Curry Gravy or try using as a replacement to Base Gravy in any highly flavoured B.I.R curries that require a base sauce.