Blanching is the heating process for prepping foods for freezing or further cooking. Blanching spinach is one of the easiest things you could possibly do in the kitchen. One method of spinach blanching is to simply put the spinach in a dry skillet. As it cooks, the water cooks out of the spinach and it shrinks. This also works well with chard and kale. To blanch spinach another way, simple boil a pot of water and throw the spinach in. Then you take the spinach out and squeeze the excess water out of it. That's it. Blanching done.