InstaMash

 is a food item found in Fallout 3. It can restore some of your Hit Points, but also gives you a small amount of radiation.

Insta-Mash is packaged in a white box with blue highlights. A tag-line toward the bottom of the box states that Insta-Mash comes with "Real Dig-In Flavor!"

The "insta" part of the name likely indicates that it is a powder to which water is added, simalor to instant puding, that as well as the tag line may indicate that there is no real potato in it at all.