Dice the onion and mince the garlic. Add both to a large skillet with the olive oil. Use a vegetable peeler or the side of a spoon to scrape the skin from the ginger. Once peeled, grate the ginger on a cheese grater straight into the skillet. Sauté the onion, garlic, and ginger over medium-low heat for about 5 minutes, or until the onion is soft and transparent. While these are cooking, dice the tomato.

Add the curry powder and cumin to the skillet and continue to stir and cook for one minute more.

Add the diced tomato and salt. Continue to cook for about five minutes more, or until the tomato has broken down and is no longer holding its diced shape.

Drain the chickpeas in a colander and give them a quick rinse. Add the rinsed chickpeas, frozen spinach, and a half cup of water to the skillet. Stir everything together and then bring it up to a simmer over medium heat. Let the mixture simmer for five minutes so that the flavors can meld and everything heats through.

After five minutes most of the water should have simmered away. Turn the heat down a bit (medium-low) and add the evaporated milk. Depending on how thick you want the sauce, you can either just heat through or let it simmer until thickened. If you prefer a smoother Chana Saag, you can use an immersion blender to purée some of the mixture, or transfer half of it to a blender and carefully purée it.* I left mine chunky. Once it’s heated through, adjust the salt and curry powder to your liking.

http://www.budgetbytes.com/2013/05/chana-saag/