In a medium saucepan, combine sugar, lemonade powder, and ½ cup heavy cream. Mix until everything is well combined then add the other ½ cup of heavy cream and the milk. Mix together.
Heat over medium heat, stirring constantly until mixture is starting to boil. Remove from heat.
In a separate bowl make a slurry of the corn starch and the water. Stir until the cornstarch is fully dissolved into the water.
Mix the slurry into the pudding mixture and continue to simmer for another minute while constantly stirring.
When the pudding starts to boil remove from heat and pour into a heat resistant container and cover with plastic wrap.
Let it cool to room temperature. Then store in refrigerator for up to a week.