1. Beat the yolk, juice and flavorings in a small stainless saucepan until uniform. (Takes about 10 secs, not counting juicing the lemon.)
2. Cut stick of butter into quarters lengthwise and then cross ways many times until you have about 24 - ?? tiny cubes of butter. (Takes about 20 secs.)
3. Place yolk mixture on LOW heat and add butter bits one by one whisking as you add. Keep two or three melting bits always in the pot and add more as they disappear. Whisk constantly until all of the butter has been added. (Takes about 15 - 30 secs for each bit to melt — if they melt faster your heat is TOO HIGH. Overall takes 3 - 5 mins. Sorry about your wimpy ‘burning’ arm. Don’t put it so close to the burner!)
4. Keep whisking over low heat until the mixture thickens. (Takes about 1 - 2 additional minutes. See note above about arm issues.)
5. Try not to eat it all by yourself!

I trust the farm where I get my eggs from, though, so when I make a sauce out of them, I don’t feel compelled to heat them; though if I were using eggs from the gas station or the food mart, I probably would include that step.

I thought Julia Child, in one of her books (The Way to Cook, somewhere in the mayonnaise directions, IIRC), gave directions for heating egg yolks to 160 degrees F. That kills the salmonella, but still leaves the yolks un-solidified. IIRC again, the procedure was simply hot water and time, both carefully controlled. (I’m not at home so I can’t look it up in the actual paper-bound object.)

That makes buying pasteurized eggs unnecessary, since heat-sanitizing them yourself is easier than, well, clarifying butter.