This is absolutely deadly. Jared recommends it.
2 eggs
1/4 cup soft butter
1 cup semi-sweet chocolate chips
2 tsp vanilla
1/2 cup milk
Have your child (age permitting) crack the eggs into the blender container, then measure in the butter, chocolate chips and vanilla. Blend until smooth-ish, scraping down the sides a couple of times to keep everything mixed up.
Meanwhile, heat the milk to a boil - a glass measuring cup in the microwave is a great, tidy way to do it. While the blender is running, pour the hot milk through the small opening in the top and blend for a couple of minutes or so, scraping down the sides once or twice. The hot milk will melt the chocolate chips so the mixture becomes smooth and creamy.
Pour mousse into small dessert dishes and chill for at least 3 hours or until set. Serve topped with a blob of whipped cream.