In a dry pan pour coriander seeds, cumin seeds, peppercorns, fennel seeds, cloves, dried red chilies, cinnamon stick, and cardamom and roast over medium flame for about 3 minutes.Transfer the roasted spices to a plate and let them cool completely and then grind them into a fine powder.Then also mix turmeric powder, red chili powder, and nutmeg powder in the ground spices.
Now let's prepare potato filling. Heat oil in a pan and add mustard and cumin seeds.Once they splutter add chopped onion and until it becomes transparent. Add ginger-garlic paste and cook for one minute.Add mashed potatoes, dabeli masala, salt, and lemon juice. Cook for 2-3 minutes. Add chopped coriander leaves, mix well, and set aside.
Slice the pav horizontally but not all the way through. Apply butter on both sides of the pav.Spread a generous layer of green chutney on the bottom half of the pav.Add a spoonful of potato filling.Drizzle tamarind chutney over the potato filling.Top with chopped onions, sev, pomegranate arils, and coriander leaves.Serve immediately and enjoy!