Definition: This term means to plunge foods into boiling water for a few seconds or a few minutes, then remove and place in ice water. This process sets the color of vegetables, lets you easily peel fruits, and slip the skins off nuts. The food does not cook all the way through, so crisp texture is preserved. Blanching also denatures enzymes that make food spoil as the first step in food preservation.
Examples: To set the color of the asparagus, briefly blanch in boiling water.
To blanch, bring a large pot of water to a boil. Trim the ends of asparagus and green beans, and cut other vegetables into the size you want to use in the recipe. Leave fruits and nuts whole; you might want to cut a small "x" into the skin of fruits to help make peeling later easier. Get a large bowl full of ice water ready.
Put the vegetables into the boiling water for about 30 seconds, just until the color intensifies. Remove them as quickly as you can, being careful not to splash yourself with boiling water. Plunge the food immediately into the ice water bath and let stand until cold. At this point, you can slip the skins off of fruits and nuts.
Then remove the food from the ice water bath and use in the recipe.