I'm sure there are lots of tutorials out there, videos even. So I'll be quick.
Here's what you need:
A disposable plastic bowl, the size you want your igloo to be
A disposable plastic cup for your igloo's entrance
A bag of miniature marshmallows
A sh**load of powdered sugar
This is how it's done:
Cut 1/3 off your cup, place it on the plate.
Cut the shape of your "entrance" in your bowl, use some tape to fix
Squeeze your lemon, just use a couple of drops and mix them into the powdered sugar. You want a thick consistency.
Now start building! Dunk your mini marshmallows into the sugar/lemon icing and basically build your way around and up your plastic structure!
The marshmallows are really forgiving. They allow another one to squeeze inbetween them if necessary! To be honest I expected this edible craft to end up at CraftFail like so many others of my projects. Hey, I am happy to reaport that this one turned out just fine! :-)