Add cashew nuts and melon seeds to a bowl. Pour water and allow them to soak for 30-40 minutes. After the soak time is over, add soaked cashews and melon seeds mixture to a blender and blend until smooth. The melon-cashew mix should be smooth, not gritty in texture.
Heat mustard oil in a large pan over medium heat. Add whole black cardamom and bay leaves.
Lightly sauté the whole spices in oil to release their aroma and flavor. Add cumin seeds to the whole spices.
As they start to crackle, stir in the ginger-garlic paste.
Cook until the raw smell is gone.
Add the minced onions and green chilies.
Cook for 2 minutes over medium heat, stirring in between to avoid burning.
Stir in tomato purée and tomato paste.
Cook for 3-4 minutes over medium heat until the oil separates.
Add whisked yogurt, coriander powder, Haldi powder, Kashmiri red chili powder, and salt.
Add tandoori masala powder and mix until everything is well blended.
Add the melon-cashew mix to the simmering masala. Mix it well.
Stir in garam masala powder, kasoori methi, and mix again.
Close the burner and allow the masala to cool completely.
Transfer it to a blender, add 1/4 cup of water, and pulse, until smooth.