Peel potatoes if desired. Cut potatoes into small (1-1 1/2 inch) pieces of roughly uniform size. Put potatoes into Ziploc® Brand Zip 'n Steam® bag.
Seal bag. Pat potatoes into single layer. Place in microwave.
Microwave on full power for 6 minutes (for 2 servings) or 7 1/2 minutes (for 4 servings), or until all potatoes are tender and smash easily when pressed. If needed, microwave for additional 30-second intervals until all potatoes are tender.
Allow bag to stand for 1 minute before handling. Carefully open bag. Leave cooked potatoes in bag.
Add milk, butter, and salt to bag.
Squeeze air out of bag and seal. Hold top edge of bag in one hand and cover other hand with a clean dish towel. Use covered hand to mash potatoes by squeezing bag.
If needed, add additional milk (1 Tablespoon at a time) and continue mashing until you reach your desired consistency. Add additional salt or butter as desired, mashing until combined.
Check out www.healthypotato.com for more great tasting quick and easy potato recipes from the United States Potato Board.