Preheat your oven to 375°F (190°C).
Remove the outer leaves of the cabbage and cut out the core.
Heat oil in a skillet over medium heat. Add cumin seeds and let them splutter.
Add chopped onions and sauté until golden brown.
Add ginger-garlic paste and cook for another minute.
Add tomato puree, turmeric powder, red chili powder, garam masala, and salt. Cook until the oil separates from the masala.
Add water and bring the mixture to a boil.
Place the whole cabbage in the skillet and spoon the masala over it, making sure it is well coated.
Transfer the cabbage to a baking dish, cover with foil, and bake for 30-40 minutes or until the cabbage is tender.
Garnish with chopped cilantro before serving.