In medium saucepan over medium heat, whisk together half and half, cake mix, sugar and salt until warm.
In a medium bowl, mix together egg yolks and vanilla.
Using a ladle, slowly drizzle about a 1/2 – 1 cup of the warm mixture into the egg yolks, whisking constantly.
Add the yolk mixture to the warm half and half mixture while again whisking constantly.
Continue heating while continually stirring and scraping the bottom of the pan until the mixture thickens and the temperature reaches between 170 – 175° F on a thermometer.
If you find that the mixture has clumps after heating, pour through a fine mesh sieve into a bowl. Otherwise, pour mixture into a medium bowl, place a piece of plastic wrap over the surface and refrigerate for a minimum of 2 hours (though 4 hours is best) to completely cool.
Place in ice cream maker and follow manufacturer’s directions.
Before placing ice cream in a container to freeze, mix in sprinkles or do so when directed by ice cream manufacturer.
Serve immediately for soft serve ice cream or pour into an airtight container to store in the freezer to enjoy later.