Best vanilla fudge EVER

I'm biased, but I think this may be the best fudge you will ever have. My grandfather used to make batches of it over Christmas and New Year much to the delight of myself, my siblings and my cousins. It uses Lyle's Golden Syrup, which is a bit of an exotic item in the USA, but can easily be obtained online or from places like World Market.

Ingredients

• 1 tin condensed milk
• 8 tablespoons warm water
• 5 oz butter, cut into small chunks
• 1.25 lbs caster sugar
• 3 tablespoons Lyle's Golden Syrup
• pinch of salt
• 1/4 - 1/2 tsp Vanilla essence
• butter or olive oil to grease tin

Preparation

Grease a 10" square tin (or one of similar capacity) and set aside. 

Place condensed milk in a large thick bottomed pan (I use a 5 quart dutch oven) together with the butter, sugar, syrup and salt. Use the warm water to rinse out the condensed milk tin and add that too.

Heat gently -- do not let the mixture boil -- until all the sugar has dissolved. Check for grittiness on the bottom of the pan: once it has all gone then you may increase the heat. You want to raise the temperature to what is known as "soft ball" to those using candy thermometers, or 240F (115C) to the rest of us. (Crucial tip if you live at altitude: for every 1000' above sea level reduce the target temperature by 2F, e.g. I'm at 9000' so "soft ball" is 222F. See https://bakingwithaltitude.com/high-altitude-candy-making-tips/ for more details.) This is obviously pretty damn hot and since the fudge mixture is very sticky be careful while stirring it -- you do not want to end up slopping any of it onto yourself. And you will need to stir things periodically to prevent the fudge from catching on the bottom of the pan as it heats up. Expect the mixture to be bubbling away quite vigorously and darkening in color as it gets hotter.

Once it's reached "soft ball" stage you can test that it will set properly by dropping a little into some ice cold water. If it forms a firm soft ball that holds its shape you're golden. If you don't have a thermometer to use at all the test-in-ice-cold-water trick is a reasonable surrogate, but until you have an eye for what "ready" fudge looks like it can be an exercise in frustration as you try and wait and try and wait to get fudge that will set. I digress...

Of course, if you're feeling confident in your thermometer you can just press ahead. I know from experience that mine is trustworthy so no longer bother messing about dropping hot liquid fudge into water.

If you're at all in doubt about the fudge being ready wait a little longer as firm-extra-well-set fudge is much nicer than sloppy-will-not-ever-set fudge.

Once ready, remove the pan from the heat and allow to cool slightly (just a few minutes) and then add in your vanilla essence. Beat the mixture hard until it starts to get stiff then quickly pour into your tin. Allow to set a few minutes before cutting into small squares -- this is much easier done before the fudge sets completely.