Heat the olive oil in a wide pan or braising pan over medium heat. Add the coriander, cumin, and fennel seeds and toast until fragrant and beginning to pop, about 1 minute.

Add the onion and salt. Cook, stirring occasionally, until the onions are softened and starting to brown, about 10 minutes—adjust the heat between medium-low and medium if they seem to be scorching rather than softening.

Stir in the garlic, ginger, and green chili. Cook until very fragrant, about 2 minutes, then pour in the water and increase the heat to medium-high to bring it to a simmer.

Add the spinach and cover the pan. Cook just until the leaves have wilted, about 2 minutes.

Transfer the mixture to a blender and stir in the ice cubes to cool it rapidly, which locks in the bright green color. Blend until the gravy reaches your desired consistency, whether slightly textured or perfectly smooth.

Wipe out the pan and heat more olive oil over medium heat. Add the pressed tofu cubes and salt, cooking and stirring occasionally until the edges are lightly browned and crisp, about 10 minutes.

Stir in the turmeric until the tofu pieces are evenly coated, then pour the spinach gravy back into the pan. Bring to a brief simmer for 2 minutes to meld the flavors, then remove from the heat and stir in the garam masala and lime juice.

Adjust salt to taste and serve hot with rice or flatbread.