Scald half-and-half in top of double boiler. Add sugar and stir until dissolved. Add malted milk powder; mix. Cool.

By spoonful, add one quarter cup hot half-and-half to beaten eggs. Slowly pour egg mixture into remaining hot half-and-half in a fine stream, stirring constantly. Return mixture to double boiler and cook, stirring until mixture thickens slightly and coats the spoon. Remove from heat and chill thoroughly (overnight).

Add vanilla and pour into ice cream maker and freeze following manufacturer's directions.