Stir together your whole milk, heavy cream, sugar and vanilla extract in a large bowl for about 2 minutes until the sugar starts to dissolve.
Pour in the lucky charms cereal and fold it into the milk mixture. Cover and place in the fridge for at least 2 hours, up to overnight.
Pour the mixture through a strainer to get out all the cereal pieces. Press down on the cereal with a rubber spatula to get as much of that flavorful milk out as possible.
Pour the milk mixture into your prepared ice cream maker and churn according to directions.
Scoop some of the ice cream into a 5qt bread pan, then add about 1/3 of the lucky charms marshmallows on top. Carefully stir them throughout with a knife or spoon. Repeat with more ice cream, and more marshmallows till you've used all of it.
Top with a few extra marshmallows.
Cover and freeze for 6 hours, up to overnight then serve.