Combine the milk and cream in a medium saucepan. Cook over medium-low heat until bubbles form around the edges, and the temperature reaches 170ºF.

Meanwhile, add the egg yolks and sugar to a deep bowl. Whisk until the yolks become thick, airy and pale yellow.

Slowly whisk in the hot milk mixture (do not rush this process, called tempering, or else your eggs will curdle). This is now your custard base.

Pour the custard back into the pot. Cook over low heat, stirring constantly with a wooden spoon, until the custard becomes just thick enough to lightly coat the back of the spoon, about 10 minutes.

Pour the custard through a sieve to strain out any bits.

Fill a very deep bowl with ice and cold water. Nestle the bowl with the custard on top, and stir to quick cool the custard. Transfer to a glass jar, and chill overnight before using as a base to make your gelato.