Kid Food: Chocolate Mousse

This is another winner in the dessert field - my in-laws go nuts for it.
 
Melt 2 bars (200g total) dark chocolate with 1/2 a can evaporated milk (Ideal or Carnation are the brands I know of) over low heat until smooth.
Add a small packet of white marshmallows (100g or so), stir until melted in.
Whip remaining 1/2 can evaporated milk until it's pretty stiff, then fold into the chocolate mix. (Reserve pot-licking rights and get to it before it cools too much)
Pour into a serving dish and refrigerate overnight.
Garnish (if you want) with crumbled peppermint crisp, whipped cream or similar.  (Reserve rights to the settled-out bottom layer in the serving dish...)