Toss paneer with turmeric in a medium bowl until coated. Heat oil in a large nonstick skillet over medium heat. Add the paneer and cook, flipping once, until browned on both sides, about 5 minutes. Transfer to a plate. Drain oil into a large sauce pan.
Add onion and jalapeño (if using) and cook, stirring frequently, until golden brown, 7 to 8 minutes. Add garlic, ginger, garam masala and cumin. Cook, stirring, until fragrant, about 30 seconds. Add half the greens and salt. Cook, stirring, until hot, about 3 minutes.
Blend the remaining spinach/greens with just enough water to keep the blender spinning and use a plunger if it seizes. Cook until most of the excess water is gone. Remove from the heat and stir in yogurt and paneer, sweeten with a few drops of stevia to cut bitterness.
Enjoy with a grain free tortilla
