Blanching is usually done with vegetables to retain their colour. Meats, including chicken breast, can also be blanched, either to remove bacteria or to prepare the chicken for a specialised cooking process such as a blanquette -- where neither the meat nor the butter can be browned so that the dish remains white in colour. It's also common to blanche meats before stir-frying to speed up the cooking time and reduce bacteria.
Fill a pot with about 2 quarts of cold water, or enough water to completely submerge the meat.
Stir salt into the water to help in the tenderising process as the chicken breasts cook.
Rinse chicken breasts under cold water and add them to the pot. Place the pot on a stove turned to high heat.
Bring the water to a boil. Once the water starts boiling, use kitchen tongs to remove the chicken from the water and turn off the heat.
Drop the chicken breasts in ice water. This will stop the cooking process and make the meat easier to handle when finishing your recipe. This step is optional.
If the water is already boiling when you add the meat, blanche for only two to three minutes to avoid overcooking the meat.