Place the ginger and garlic in a blender with 1/4 cup of water, and blend to a smooth paste.
Heat a large skillet with a lid over medium-low heat, and scoop the ginger-garlic paste into the skillet. Sprinkle with garam masala, and stir to combine. Reduce heat to low, cover, and simmer the paste for about 15 minutes, checking to see that it hasn't cooked dry. Add more water if the mixture gets dried out. Stir in the spinach and kale, and cook, stirring occasionally, until the greens are bright green and limp, about 10 minutes.
Place the milk and cottage cheese into the blender, and blend until smooth. Add a pinch of salt and nutmeg to the blender, and pulse again just to mix.
Heat the ghee in a skillet over medium heat, and cook and stir the onions until they are translucent, about 5 minutes.
Stir the cottage cheese mixture and the cooked onions into the skillet with the greens until well combined, let cool slightly, and place about half the saag into the blender. Pulse until smooth, return the blended mixture to the skillet, and stir well.