Preheat the oven to 300ºF. In a large bowl, combine the cornflakes, milk powder, sugar, and salt by hand, squeezing and crushing the cornflakes at the same time until coarsely crushed. Stir in the melted butter until small clusters form. Transfer mixture to a baking sheet and bake for 15 minutes. Remove from the oven and cool completely.

Add the cereal to the milk, and stir until fully soaked; let steep for 45-60 minutes.

Place a fine-mesh sieve over a medium bowl and strain out the milk. Using the back of a spoon, wring the milk out of the cereal, but don’t force the cereal through the sieve. Discard the soaked cereal. Stir the sugar and salt into the milk; set aside.**

In the bowl of a stand mixer, fitted with the whisk attachment, beat egg yolks, sugar, and salt on high speed until yolks lighten in color and thicken into a ribbon as you lift the whisk out of the bowl, about 3 minutes.

In a medium saucepan, whisk together egg yolk mixture, heavy cream, and cereal milk. Cook over low heat until mixture is thick enough to coat the back of a wooden spoon.

Immediately pour the custard mixture through a fine mesh sieve over a bowl or large glass measuring cup. Whisk in the vanilla until smooth. Cover and chill the mixture thoroughly in the refrigerator.

Once the custard mixture is chilled, freeze in an ice cream maker, following the manufacturer's instructions. Transfer to a freezer-safe container, and freeze for at least 2 hours, or up to 3 weeks.

Serve ice cream with cornflake crunch.