In a medium-sized saucier, or similar pot with curved sides, heat the heavy cream and milk over medium heat. Give the mix a whisk to combine the milks together. Add the salt and vanilla extract, and bring the milk base to a gentle simmer. Avoid allowing the mix to boil.
Once you see tiny bubbles on the edge of the milk, and steam coming off the surface, turn the heat off. Add the cereal to the milk base. Whisk the cereal into the milk to distribute throughout the milk as much as possible. Allow the cereal to infuse into the milk for fifteen minutes.
While your cereal is infusing, combine the egg yolks and sugar in a medium-sized mixing bowl. Whisk the eggs so the sugar is dissolved and the eggs take on a lemon-yellow color. Once the fifteen minute infusion time has elapsed, return the milk to the stove and heat, over medium heat, until you see the milk steaming (about four minutes).
Once the milk has begun steaming, use a one cup ladle, or a measuring cup, to carefully scoop out some of the hot milk mixture. Gradually whisk the milk into the eggs in a slow trickle. After you've added all of the hot milk, reintroduce the milk-egg mixture to the milk in the pot in the same way. Once you've added all of the milk-egg mixture to the hot milk in the pot, whisk to combine.
Allow the cereal milk custard base to cook for three to four minutes, or until the mixture thickens to the consistency of ketchup. Don't let it boil! Take a wooden spoon and dip it into the custard base. You should be able to draw your finger down the middle of the back of the spoon and the custard shouldn't run into the divide. If it does, it needs to cook for 2 minutes longer (whisk constantly to prevent lumps).
Remove the pot from the stove, and let the cereal milk custard base infuse for another ten minutes. After the second infusion time has come to an end, set a strainer on top of a medium mixing bowl. Pour the custard base into the strainer to remove the big cereal chunks. Discard the cereal.
Let the custard cool to room temperature before covering with plastic wrap and refrigerating until completely cold. Refrigerate from 4-24 hours.
Once you're ready to churn, pour the custard into your ice cream maker and churn according to the manufacturer's instructions. When the ice cream is a soft-serve consistency, you can eat it as is, or you can transfer it into an ice cream container and freeze for two to three hours for a firmer consistency.
Serve with, or without, extra crushed cereal on top, or on its own. The frozen custard should keep for up to two weeks in the freezer.