this fudge recipe from Hope and Greenwoods 'Life Is Sweet' which is so far the best I've found and the bench mark against which all other fudge has been measured for the last 3 years (the salt in that recipe was my own addition and totally unnecessary).
The thing is that without a sugar thermometer I wouldn't be making fudge at all. My sister and I had a go at it many years ago, we wasted a lot of ingredients trying to make 2 batches and totally messing it up. What the recipe failed to adequately explain was just how bloody long it takes, all it said was bring to a rolling boil after the sugar has melted and that it was done when it made a soft ball in cold water. You can get what looked for all the world to us like a soft ball long before we were really at the soft ball stage (somewhere about 112 degrees C) and it's not like you can stick a finger in to see how you're getting on. It was a bit vague on the stirring bit as well - Miss Hope makes it clear that a good ten minutes with an electric beater is called for, a couple of minutes with a wooden spoon (which is as long as any reasonable person is likely to want to beat something with a spoon for) just won't do the job.
My sugar thermometer is a fairly unsophisticated model (it came with a warning not to expose it to extreme temperatures which was a little bit worrying), I have occasionally hankered after a swish probe sort of a thing which would give exact readings on some sort of easy to see display panel (no more squinting through clouds of steam nose a mere inch or two from a volatile pan of boiling sugar and fat) but I wouldn't swap this one for two reasons. It was a present from my dad who had heard me mention that it's something I wanted so went to the trouble of finding one and posting it down from Shetland as a surprise. It's not the first time he's done something like that but it's enough of a novelty to invest the thermometer with a certain sentimental attachment (I'm also sentimentally attached to a small adjustable spanner, thanks dad!). I also prefer things that aren't battery operated because I can guarantee that the batteries will fail at the most inopportune moment possible.
It's amazing the difference the right gadget makes. It's not impossible to make jam without a sugar thermometer, all it takes is a cold plate to check for setting points, but it's so much better when you can take the guess work out of it. Watching the thermometer creep towards the magic temperature has given me a far better idea of how long it takes and helped me notice how the textures change (it hasn't stopped me letting things boil over because I turned my back for a moment at a critical stage or was overly optimistic about how much would go in the pan). Fudge, as I've said, is beyond me without one. Post thermometer fudge has become a Christmas staple (everyone gets a bag of it, like it or not), and there's a whole world of other sweets it opens up (for better or worse I swear this will be the year I make Turkish Delight).