You might be disappointed that I'm going to tell you you need a piece of equipment which you may not already have. This is a sugar thermometer. If you search online, there is a lot of stuff about making fudge without a thermometer, judging by eye and appearance when the fudge is cooked the right amount. Feel free to do this if you wish. I have a (sometimes irritatingly) analytical mind, and so I simply couldn't cope with just 'judging' by eye. That's why I like to use a thermometer. If you're OK without, then I envy and admire you. If you're not, I bought mine for something like £6 online, it's really not a big deal.
- It doesn't matter what kind of sugar you use. Different kinds will give you different colours and flavours of fudge, but apart from that, sugar is sugar.
- I use milk for my liquid - normally full-fat. I've never tried it with water, so although technically it should work (according to the science), I don't know how edible it would really be. I advise using milk, and not less than full-fat. You can even use cream as your liquid if you want it really rich, although I haven't tried that before either.
- I use a ratio of about 2 sugar : 1 milk. Like I said, you could use any proportion you like. It's the amount of sugar that will define how much finished fudge you have - if you do 1 sugar : 10 milk, it will take forever to boil, and you'll end up with the same amount of fudge if you used the same amount of sugar with half the milk. I find this is the ratio that has the least wasted liquid. Different recipes use slightly different amounts, but mostly they're somewhere around here.
- If the analogy clicked with you, you should already know what to do really. Heat it up next. The heat you use will depend on allsorts - your oven, the amount you're making, your susceptibility to stress. If in doubt, start of low and crank it up until it seems to be doing what you want it to be. So, first, heat it up until the sugar has completely disappeared into the milk. With the amount of sugar we're using, it won't fully dissolve in room-temperature milk, so part of the heating is just to get it to dissolve. It's important that you don't stop stirring between now and the time it's going to set. This could be up to 45 minutes or even an hour, depending on your technique and experience. If you're likely to be interrupted, wait until later.
- Once it is dissolved, keep on heating it until it boils. It can be pretty ferocious when it's boiling, but just try not to panic. You will probably need a pan much bigger than you expect based on the amount of original ingredients. That is to say, if he mixture is halfway up the side of the pan before you heat it up, it will definitely boil over. If in doubt, use a bigger pan than you think you need. Make sure you don't stop stirring at all while it is boiling. You know when you're making a whitesauce and you have to keep stirring it or it'll stick to the bottom? It's like that, but much more important. Don't stop stirring, it will burn. That said, if it does burn, it's not necessarily ruined, try to avoid scraping up the burnt part and just keep the rest of it moving around. As it boils, the level will reduce slightly in the pan - this is because of the liquid boiling off, it means it's working. It could take anywhere between 10-25 minutes to get to the right temperature, what with all the different factors involved.
- Now use your thermometer to measure the temperature. When it's at the right temperature, you can turn it off and stop cooking, but don't stop stirring. If you do, it will crystallise unevenly, and might end up grainy or lumpy. Instead, keep on stirring and stirring. It will gradually start to thicken up. This will likely take longer than it took to boil, but don't lose heart. If it cooked at the right temperature, it will thicken. It's when you turn off the heat that you can add extra ingredients. You could add a spoonful of butter for richness, chocolate or vanilla for flavour, anything you want really. The sooner you add ingredients after taking it off the heat, the better they will be mixed in. But if you're adding chunks of things (such as nuts), it's fine to wait until you're almost ready to put it to set.
- Deciding when you leave it to set it a personal judgement, I'm afraid. It should be thin enough that you can still physically stir it, but thick enough that it makes your arm a bit achey after a while. It doesn't matter that much, so try not to worry about it.
- It will set by the time it's cooled to room temperature. Now you can cut it up or do what you will.
It's likely that your first batch will go wrong. I don't want to dishearten you, but just try to be open to the possibility. It might burn, it might not set, it might be too hard or brittle. You might know what went wrong or you might not. I still regularly make complete mess-ups. In fact the first batch I made in planning this post just didn't set. I don't even know why, sometimes you can't know. Just have faith and try again, one day you will make a perfect batch and it will all be worth it.