Place the spinach in a steamer over medium-high heat and steam for about 3 minutes, or until the leaves are wilted and cooked.
While the spinach steams, heat the oil in a skillet over medium heat.
Add the diced onion and cook for 3 to 5 minutes until translucent.
Stir in the garam masala, coriander, garlic powder, and salt.
Cook for another 2 to 3 minutes, stirring frequently to toast the spices and prevent sticking.
Transfer the steamed spinach, the cooked onion and spice mixture, and the lemon juice to a blender or food processor.
Blend until smooth.
Return the pureed spinach mixture to the skillet.
Add the cubed tofu and stir to combine.
Warm over medium-low heat until the tofu is heated through.
Transfer to a serving dish and enjoy immediately.