What do you need?
a saucepan
water
fresh free range organic eggs, room temperature
a food thermometer
Sometimes you want to eat something delicious that contains raw eggs, such as mayonnaise, ice cream or tiramisu, for example. If raw eggs don't go on the fire or in the oven, you run a (minor) risk of getting sick.
Those eggs may contain salmonella bacteria, especially when the are older, Because we mostly cook&bake with/for children, we don't want to take any risk, We feel raw egg is a bad idea and by pasteurizing the egg you destroy those bacteria.
So we only use pasteurized egg yolks or whites. We usually buy pasteurized egg whites in a packet at the supermarket, but you can also do it yourself. We could not find pasteurized egg yolks at the supermarket, but pasturizing egg yolks you can also do at home.
On wikihow you can read and see step by step how that works, but you do have to work very precisely!