Heat: In a medium saucepan, combine the cream, milk, sugar, corn syrup, and salt. Heat over medium, stirring occasionally, until steaming but not boiling.

Whisk Yolks: In a separate bowl, whisk the egg yolks until smooth.

Temper Eggs: Slowly drizzle some of the hot cream mixture into the yolks, whisking constantly. Repeat with several more spoonfuls of hot cream (this process slowly warms the eggs, so they don’t scramble). Then pour the tempered yolk mixture back into the saucepan.

Cook Custard: Cook over medium-low heat, stirring constantly, for a just a few more seconds, until 170-175 degrees F (or the mixture thickens just slightly and coats the back of a spoon). Do not let it boil. Remove from heat and stir in vanilla extract.

Strain the custard through a fine-mesh sieve into a clean container.

Chill, covered, in refrigerator for at least 4 hours or ideally overnight.

Churn cooled custard in an ice cream maker according to manufacturer’s instructions. Add mix-ins* during the last few minutes of churning, if desired.

Freeze to set: Transfer to ice cream containers and freeze for at least 4 hours, until firm and scoopable.