If you don’t want to use raw eggs do this: whisk the egg yolks and sugar over a bain marie (double boiler). Whisk constantly, until the sugar is dissolved, and the custard thickens. The temperature of egg yolk should reach 154-158ºF (68-70ºC). Make sure the bottom of the bowl doesn’t touch the water. This process called pasteurizing and it’s killing bacteria’s such as Salmonella. You can see how I make this process in the video above. This step is totally optional and if you are using fresh eggs there is no real danger. But, many people intimidate eating raw eggs so it’s up to you.