To make this gelato base (which can also be made without eggs), start by combining milk and cream in a saucepan and cook gently over medium-low heat (do not allow it to boil). In a bowl, whisk together egg yolks and sugar until thick and light yellow. Once the milk and cream mixture reaches 170°F, slowly incorporate the hot liquid into the yolk mixture, whisking constantly. Transfer the mixture back to the saucepan and cook, stirring constantly, until the temperature reaches 185°F.
Create an ice bath by filling a bowl with ice and water. Using a mesh strainer or piece of cheesecloth, strain the custard into a bowl set over the ice bath. Stir the mixture until it’s cooled to room temperature. Add salt, cover and refrigerate for at least 6 hours.
At least an hour before the next step, place a jellyroll pan, metal spoon and spatula in the freezer. After chilling, pour a third of the gelato mixture onto a cold jellyroll pan and return pan to the freezer uncovered for 20 minutes.
Using a bench scraper or stiff spatula and working from the freezer, scrape the frozen gelato mixture off the pan and into the refrigerated base.
With a whisk, stir until the frozen gelato is fully incorporated.
Pour directly onto the pan without removing it from the freezer. Using the spoon or spatula, spread the gelato mix evenly onto the pan. Leave uncovered and close the freezer.
After 45 minutes, check the consistency. The gelato is ready when the sides are frozen and the middle is mostly frozen but not slushy. If the middle appears runny, freeze it for another 15 minutes.