Place the coriander seeds, fennel seeds, black peppercorns, and dried red chilies in a small pan over low heat. Dry-roast for 2 minutes, stirring constantly, until the spices are aromatic and slightly darker. Transfer to a plate to cool completely. Once cool, grind in a spice grinder or crush in a mortar and pestle to a coarse powder. Do not grind to a fine dust; you want small cracked pieces of coriander.

Heat 1 tablespoon of oil in a kadai or deep sauté pan over medium-high heat. Add the onion petals and bell pepper squares. Sauté for 2 minutes until the edges are slightly blistered but the vegetables still retain their crispness. Remove them from the pan and set aside on a plate.

In the same pan, add another 2 tablespoons of oil (or ghee) over medium heat. Add the finely chopped onions and cook for 5 minutes, stirring occasionally, until they turn light golden brown.

Stir in the ginger-garlic paste and slit green chili. Sauté for 1 minute until the raw smell disappears. Add the tomato puree, turmeric powder, Kashmiri red chili powder, and salt. Cook this mixture for 7 minutes, stirring frequently, until the moisture evaporates and you see oil separating from the sides of the masala paste.

Add the prepared ground kadai masala to the tomato paste. Stir well to combine and cook for 1 minute. Pour in 1/2 cup of water to create a thick, coating gravy. Bring to a simmer.

Gently fold in the sautéed bell peppers, onions, and paneer cubes. Simmer on low heat for 2 minutes to allow the paneer to heat through and absorb the flavors. Stir in the heavy cream (if using) and crushed kasuri methi. Garnish with chopped coriander leaves and serve hot.