Pour cream into a small sauce pot and add saffron
Bring to a simmer and turn off heat
Beat egg yolk, salt and lemon juice very thoroughly and refrigerate
Reduce cream by about a third
Temper the egg mix by adding the hot cream to it very slowly, whisking the whole time.
When about a third of the dairy has been whisked into the egg mix, pour the egg mix into the sauce pot and return to a simmer, whisking constantly.
The mix will go from thin to thick abruptly. Don’t miss it, otherwise you wasted food. Shame on you.
Test for seasoning and put the sauce on just about anything.