Cut the paneer into 1-inch cubes and pat dry with a paper towel.
Heat the ghee in a large non-stick skillet over medium heat. Add the paneer cubes and sear for 2-3 minutes per side until golden brown, then remove from the pan and set aside.
In the same skillet, add the diced onion and sauté for 5 minutes until translucent and soft.
Stir in the minced ginger and garlic, cooking for 1 minute until fragrant.
Add the turmeric, garam masala, cumin, sea salt, and black pepper, stirring constantly for 30 seconds to toast the spices.
Add the fresh spinach and water to the skillet. Cover and steam for 2-3 minutes until the spinach is completely wilted.
Transfer the spinach mixture to a blender and pulse until mostly smooth, then return the sauce to the skillet.
Reduce heat to low and whisk in the Greek yogurt until fully incorporated and creamy.
Add the seared paneer back into the sauce and simmer gently for 3-4 minutes to heat through before serving.