In a heavy bottomed medium saucepan, gradually whisk one C. of the milk into the corn starch until the corn starch is dissolved. Whisk in the remaining milk and cream. Cook over medium low heat, stirring constantly, until the mixture is simmering and slightly thickened, about 8 to 10 minutes. Mixture should look frothy, not a full boil. Whisk in the dulce de leche.
Strain into a medium bowl set in a larger bowl of iced water. Stir in the vanilla. Let sit, stirring frequently, until completely chilled.
Pour the mixture into the container of an ice cream maker and freeze according to the manufacturers instructions. Transfer the frozen ice cream to a large, airtight container. Cover and freeze until firm and set, about 4 hours. Serve frozen.
Make the peaches when the evening is getting real lazy and the fire on the grill is burning down. Simply place them on the grill for 4-5 minutes, just when the grill marks appear – turn for a few minutes more only if they are firm enough to hold up. Spoon the peaches over the ice cream. Ponder how it doesn’t get any better than this.