Prepare tofu - Bring a large pot of salted water to a boil. Drain the tofu and pat with paper towels to remove excess water. Chop the tofu into cubes.
Add the cubed tofu to the boiling water and boil for 2 minutes. Use a strainer to remove the tofu from the water and drain immediately. Set aside on a dry towel.
Blanching the spinach: Use the same pot in which you boiled the tofu. First prepare an ice bath (a large bowl of ice water). Submerge the spinach leaves in the boiling water and blanch for 2 minutes, or until wilted yet still bright green. Immediately transfer to the ice bath to stop cooking. Once the water is cool, squeeze out as much water as you can and set aside.
For the spinach mix: Add the blanched spinach to your blender with the remaining ingredients for the mix. Bled until smooth.
The masala base: Heat a large pan over medium heat with the oil. Once the oil is hot, add the cumin seeds and fry for 30 seconds, or until a bit darker and fragrant. Add the chopped onion and cook for 4-5 minutes, or until brownish and translucent. Add the ginger and garlic and cook 1-2 minutes until the raw smell goes away. Add the turmeric, coriander, cumin, red chili powder, salt. Cook for 30 seconds, stirring them well.
Reduce the heat to medium-low. Pour in the spinach mix and cook for around 5 minutes, until the mixture is thick, stirring occasionally and adding more water if required.
Add the garam masala and, crushed the fenugreek leaves (if using) into the gravy. Add the tofu as well and and gently mix to combine and cook for 2-3 minutes or until the mixture is heated through. Take it off the heat and squeeze lemon juice on top.
Garnish with coriander and serve with basmati rice or Indian flatbread.