Firstly, grind 1 kg of tomatoes to a smooth paste and keep aside.
In a small bowl, take 1 tsp tumeric, 1½ tbsp chilli powder, 1 tsp coriander powder, ½ tbsp garam masala.
Prepare a smooth paste by adding ½ cup of water. Keep aside.
In a large kadai, heat ½ cup oil. Add 4 bay leaf, 2 cinnamon, 1 tsp cloves, 2 pods black cardamom, ½ javetri and 1 tsp cumin. Sauté on a low flame till the spices turn aromatic.
Add 2 tbsp of ginger-garlic and sauté well.
Now add 5 onions and sauté until golden brown.
Further, keep the flame on low and add the prepared masala paste, stirring until well combined.
Cook till the oil separates from the sides.
Add the tomato puree and cook until well combined.
Also, add 2 tbsp of salt and cook until well combined. Be careful as the base starts to splutter.
Cover and cook till the oil separates.
Now add 1 cup of cashew paste and cook until well combined. Continue cooking until the oil separates.
Add 2 tbsp kasuri methi and mix well.
Finally, store Gravy Base in an airtight container and refrigerate for up to 3 months.