1. Heat 1 Tbs. butter in pot over medium heat. Add onion, and cook 3 minutes. Stir in ginger, garlic, curry powder, mustard seeds, and turmeric. Cook 1 minute. Add hash browns and broth, and bring to a simmer. Cover, reduce heat to medium-low, and simmer 7 minutes. Stir in spinach, and cook 2 minutes more, or until wilted. Purée with immersion blender until smooth.
2. Heat remaining 1 Tbs. butter in nonstick skillet over medium heat. Add paneer cubes, and cook 5 to 7 minutes, or until golden brown, turning occasionally. Spoon paneer over soup, and serve hot.