Combine the remaining milk, cream, sugar, and corn syrup in a medium saucepan. Bring to a boil over medium-high heat and continue boiling for 4 minutes. Remove from heat and gradually mix in the cornstarch slurry mixture. Bring the mixture to a boil over medium-high heat and cook, stirring with a
heatproof spatula, until slightly thickened, about 1 minute. Remove from heat.