In double boiler, heat 1/2 quart of the milk until
it comes just to the boiling point. Take 2 cups of hot milk and mix well with the
cornstarch. Slowly add this to egg and sugar mixture, stirring constantly. Add the egg mixture to the remaining milk. Stir custard slowly over medium heat,
in double boiler, until custard thickens.
Add marshmallows and stir until marshmallows are dissolved.