Cut the paneer into even 1-inch cubes and cut the bell peppers and onion into 1-inch squares so every piece cooks at the same rate.

In a large bowl, whisk together the hung yogurt, ginger-garlic paste, red chili powder, turmeric, garam masala, roasted gram flour, half the lemon juice, mustard oil, and salt until smooth.

Add the paneer cubes, bell peppers, and onion squares to the marinade and gently fold until every piece is evenly coated, being careful not to crumble the paneer.

Cover the bowl and refrigerate so the spices penetrate the paneer and vegetables and the flavor deepens.

Thread the marinated paneer cubes, bell pepper pieces, and onion layers alternately onto skewers, leaving a small gap between pieces so each side gets direct heat.

Heat a grill pan over medium-high heat and brush it lightly with mustard oil until it is hot enough that a drop of marinade sizzles on contact.

Place the skewers on the hot grill pan and cook undisturbed until the bottoms develop dark char marks and the paneer edges turn golden.

Turn the skewers and grill the remaining sides until the vegetables are charred at the edges but still crisp-tender and the paneer is warmed through.

Remove the skewers from the heat and let them rest so the residual steam finishes softening the paneer without overcooking it.

Squeeze the remaining lemon juice over the hot skewers and serve immediately with mint chutney and sliced onion rings.