Bring a pot of water to a boil and add a pinch of salt. Add the spinach leaves and blanch them for 2-3 minutes until wilted.
Remove the spinach and immediately transfer it to ice-cold water to preserve its vibrant green color.
In a blender, combine the blanched spinach, tomato, 3 cloves of garlic, ginger, and green chili. Blend until smooth and set aside.
Heat a pan over medium heat and add oil. Once hot, sauté the remaining 2 cloves of chopped garlic until golden.
Add the chopped onions and cook for 2-3 minutes until they turn soft and translucent.
Pour in the spinach puree and mix well. Add about ½ cup of water and stir.
Cover the pan and let the mixture simmer for 10 minutes, stirring occasionally to prevent sticking.
Once the spinach is cooked, add garam masala, turmeric powder, red chili powder, and salt. Stir well and cook for another minute.
Optionally, add ½ teaspoon of sugar to balance the flavors.
Mix in the heavy cream and combine well.
Gently add the paneer cubes, stirring them into the curry. Let it simmer for 3-4 minutes.
Turn off the heat, then add lemon juice and kasuri methi for extra flavor.