In a small Tupperware bowl, add the cereal and milk. Put the lid on well and shake it up a bit. Let sit at least 8 hours occasionally shaking.
When ready to make the ice cream base, use a blender to blend the milk and cereal mixture until smooth and no large pieces of cereal remain. Whisk the egg yolks and sugar in a large bowl and set aside.
In a large saucepan over medium heat, bring the cream and cereal milk to just a simmer (edges just starting to bubble), whisking constantly as the sugars in the cereal causes it to stick a bit. Slowly whisk the heated cream into the egg yolks to temper. Return the mixture back to the saucepan and cook for 3 to 4 minutes longer until thickened and evenly coats the back of a spoon. Remove from heat and stir in the cinnamon and caramel liqueur. Cool bowl in an ice bath to reduce the temperature before covering directly with plastic wrap and placing in the fridge to cool completely, 6 hours to over night.
Set up ice cream maker according to manufacturers instructions and churn the ice cream. When almost set, sprinkle in drops of brown sugar and swirl in the dulce de leche. Place in a resealable container and freeze until set.
Notes
Peabody’s overnight cereal idea for this killer ice cream recipe