I tried to make creme brulee recently. I tried three different
recipes, and every one had the same problem: it wouldn't set! After
following all the directions to the letter, I ended up with something
approximating custard. What am I doing wrong?

This may be of interest to you:

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You are probably in a high altitude region. To mak creme brulee at
high altitudes, it is best to cook the Creme Anglaise and then
refrigerate it (or not if you need the Creme Brulee that night). Cook
it to 172 degrees (adjust for your altitude). Some like to add frozen
raspberries when they cook it, (about 5-7 per ramekin), and cook on
slow for about 1 hour. For resturant level quantities, use 24 yolks
and 6 whole eggs per gallon of liquid (half milk and half
manufacturing cream).