Wash and blanch the spinach in boiling water for 2-3 minutes.
Drain and transfer the spinach to ice water to preserve its color.
Blend the spinach into a smooth paste and set aside.
Heat oil in a pan and add cumin seeds; let them splutter.
Add chopped onions and sauté until golden brown.
Stir in the ginger-garlic paste and green chilies; cook for 1-2 minutes.
Add the pureed tomatoes and cook until the oil separates.
Mix in the spinach paste and season with salt and garam masala.
Gently fold in the paneer cubes and simmer for 5 minutes.
Adjust seasoning and serve hot with naan or rice.