BOMBAY MASALA CHILE CHEESE TOASTIES

Steps:

• Hari chutney:
• Purée apple, lime juice, ginger, garlic, cilantro, mint, sugar, a pinch of salt, and 1-2 chiles, depending on how spicy your chiles are and your heat preference, in a blender, scraping down sides and adding water by the tablespoonful, until a smooth paste forms. Taste and season with more salt or sugar if needed. (You should have about 1 cup, which is more than you'll need for the sandwiches. Color will fade as it sits.)
• Do ahead: Chutney can be made 3 days ahead. Transfer to an airtight container; cover and chill.
• Filling and assembly:
• Heat oil in a medium cast-iron or nonstick skillet over medium. Add mustard seeds and cook until popping, about 30 seconds. Add curry leaves and cumin seeds. Cook, stirring with a wooden spoon, until slightly darkened in color, about 1 minute. Stir in coriander, turmeric, asafetida (if using), and 1-2 chiles. Crumble potato into pan in large pieces and add salt. Cook, coarsely mashing and tossing potatoes to coat, until warmed through, about 2 minutes. Fold in cilantro and chaat masala. Transfer filling to a bowl. Wipe out pan and reserve.
• Arrange 4 slices of bread on a cutting board. Spread some chutney over each slice. Divide filling among slices and top with red onion, green pepper, then cheese. Spread 1 side of remaining 4 bread slices with more chutney and close up sandwiches. Spread ghee over outside of top slices of bread.
• Heat reserved pan over medium. Working in batches if needed, melt a small knob of ghee in pan, then arrange sandwiches, buttered side up, in pan. Cook until golden brown underneath, about 4 minutes. Turn over and cook, pressing down occasionally with the back of a spatula or the bottom of a saucepan, until cheese is melted and other side is golden brown, about 4 minutes.
• Serve toasties with extra chutney and ketchup alongside.
• Chef's note: Sandwiches can be made in a panini or sandwich press as well, or ideally a toastie maker.