Heat remaining 4 tablespoons of oil in the now empty skillet. Add cumin seeds, followed by remaining tablespoon each of chili powder and turmeric, and finally the garlic. Cook until garlic sizzles and starts to turn golden, a couple of minutes. Add spinach and cook until it heats through, a couple of minutes. Stir in yogurt, a tablespoon at a time, until incorporated. Stir in lemon juice and a generous sprinkling of salt, followed by 3/4 cup coconut milk. Heat through again, adding additional coconut milk as needed (up to the full can) and the tofu. Adjust seasonings, including additional salt and spices to taste. Serve.