In a mixing bowl, combine yogurt, ginger paste, garlic paste, red chili powder, turmeric powder, garam masala, ground coriander, lemon juice, and salt. Mix well to form the marinade.
Add the paneer cubes to the marinade and gently coat them. Cover and refrigerate for at least 1 hour.
Preheat the grill or oven to 200°C (390°F). Thread the marinated paneer cubes onto skewers or place on a baking tray lined with foil.
Brush the paneer with a little vegetable oil and grill or bake for 10-12 minutes, turning halfway, until lightly charred and cooked. Remove and set aside.
Heat butter in a large pan over medium heat. Add cumin seeds and let them sizzle for 30 seconds.
Add the finely chopped onions and sauté until golden brown, about 8 minutes.
Add the pureed tomatoes and cook for 10 minutes, stirring occasionally, until the oil begins to separate from the masala.
Add salt to taste and crushed kasuri methi. Stir well.
Reduce the heat to low and slowly stir in the heavy cream. Cook for 2-3 minutes.
Add the grilled paneer cubes to the gravy and gently mix to coat them with the sauce. Simmer for 5 minutes.
Garnish with chopped fresh cilantro leaves and serve hot with naan or basmati rice.