How to Make It
Heat 3 tablespoons of the ghee in a large high-sided skillet over medium-high. Add onion, and cook, stirring occasionally, until softened, about 5 minutes. Add garlic, ginger, and chiles, and cook, stirring constantly, until fragrant, about 2 minutes. Add one-third of the spinach and one-third of the mustard greens to skillet, and cook, folding constantly, until wilted. Repeat in 2 batches with remaining spinach and greens until all are wilted and starting to soften.
Cover and cook, stirring occasionally, until greens are tender and softened, about 5 minutes. Transfer to a blender. Secure lid on blender, and remove center piece to allow steam to escape. Place a clean towel over opening. Process until smooth, about 45 seconds, adding 2 tablespoons water if needed. Set aside.
Heat remaining 1 tablespoon ghee in a large nonstick skillet over medium-high. Add paneer, and cook, flipping halfway through, until golden brown on both sides, about 4 minutes total. Transfer to a plate lined with paper towels, and set aside.
Transfer pureed greens back to high-sided skillet, and place over medium-low heat. Add garam masala, salt, and black pepper, and cook, stirring occasionally, until heated through and flavors have married, about 5 minutes. Add cream, and stir until smooth. Fold paneer into greens, and serve immediately with warm naan or basmati rice.