VANILLA MOUSSE: whip the cream to stiff peaks, sprinkle the sugar slowly as you continue whipping, add the vanilla and finish whipping -- then freeze
Mom gives no directions on how to freeze it. I have thought it would do nicely in a prepared pie crust (any kind), or in individual cupcake liners in a muffin pan, or it could be piped onto parchment paper and frozen in shapes. It could also be put in a bowl, and dipped out like ice cream later. Alternative: since this is basically just frozen whipped cream, you could buy a pkg of frozen whipped topping, too -- Your choice.
MARSHMALLOW SAUCE: Put the unbeaten egg white, water and sugar in a double boiler and cook over boiling water for 5 minutes BEATING CONSTANTLY with hand mixer.
Remove from fire, add the vanilla and marshmallows (cut fine) and continue beating until it makes a smooth sauce.
There are no directions as to whether to use it hot, warm or cold... but I would think it would be nice used like "hot white fudge" sauce on the mousse.
NOTE: The original recipe calls for 12 of the large marshmallows cut fine, but I figured it would be easier with the mini marshmallows (or even marshmallow creme). It says to cut them fine... so I don't know if it will be a problem to simply use the minies "as is" or if you will need to chop them smaller to make them melt better.
NOTE: I thought it was interesting that it said "remove from fire" -- this may be a very old recipe because we would have said remove from burner or stove. Just thinking.