Start by heating a bit milk with saffron and let it infuse for 5-10 minutes.
Meanwhile blanch egg yolks with sugar.
Bring milk to simmer and pour in the egg yolk – sugar preparation while constantly whisking.
Pour back in the pan and heat over medium heat, constantly stiring with a wodden spatula. When the custard coagulates, transfer in a bowl so that it stops baking. It’s important bo bake over medium heat because if it’s too hot coagulation won’t work.