Mix all the ingredients for Greek Yogurt Raita together in a medium bowl. Set in the fridge to chill.
In a large pot, add milk and bring to a boil on medium heat. Stir frequently, scraping the bottom to avoid burning.
Once boiled, turn off the heat and add lemon juice. Stir gently to separate cheese curds from whey. Add cold water to stop the cooking process.
Drain the curds into a colander and squeeze as much liquid out as possible.
Add curds to a cheesecloth and tie to the kitchen faucet to drain for 1-2 hours. The longer you leave it, the firmer the paneer will be. This paneer will last in the fridge for two weeks in an airtight container.
Add lemon juice, chilli powder, turmeric and salt to your prepared paneer. Melt ghee into a preheated pan and fry paneer on two sides. Sear until golden brown and set aside.
Use the same pan to prepare saag. Add onion and cook until translucent, about 7 minutes.
Add ginger garlic paste, mustard seeds and cumin seeds. Cook the raw ginger, garlic and spices for 1-3 minutes. Add garam masala, turmeric, coriander and chilli powder.
Use water to deglaze, while scraping the built-up flavours from the bottom of the pan. Blend mixture with a hand blender or food processor.
Add blended saag mixture back into a pre-heated pan. Reduce by half for about 10 minutes on medium heat.
Add spinach and chopped kale, cook for 5 minutes on medium low, making sure not to burn the greens.
Add paneer to the saag and let it heat through for 5 minutes. Add yogurt as a finishing touch, a teaspoon at a time, into the saag.
Serve with roti or plain white rice, with a dollop of Greek yogurt raita on the side.