Start off by lining a deep baking tray (approx 9"x9") with a couple of layers of cling film.
Butter the sides of a large heavy bottomed pan, and add the sugar and cream.
Stir gently and continuously until the sugar has melted, then turn the heat up.
Continue stirring to prevent the mixture burning, and heat until the mixture starts to boil, then turn the heat down to a low-medium
Continuing to stir, let the mixture continue to simmer until the temperature on a sugar thermometer reaches 'soft ball' stage 235°F / 113°C. The mixture will bubble and rise but once the bubbles start to subside, and become tighter, you check for soft ball stage by dropping a small amount into some iced water. If the mixture can be pressed into a soft ball, it is ready.
Once 'soft ball' has been reached, turn off the heat, and move the pan away from the heat source. Add the butter but don't stir in. Leave the thermometer in and allow the mixture to cool until it reaches 110°F/43°C
Add in the chocolate and flavourings and start to beat the mixture. Continue beating just until the mixture starts to loose its glossy appearance. Pour quickly into the waiting tray. Spread around the pan with the back of a metal spoon.
Leave to cool for a few hours at room temperature before turning out carefully and cutting with a sharp knife.
The recipe is quite easy to customise. You could replace the white chocolate with milk or dark chocolate. You could add 50ml of Baileys or any liqueur, or even top with sweets. You could also add 50g of chopped nuts, or dried fruit. Possibilities are endless.
You can freeze the fudge after it has cooled. Divide layers between greaseproof paper, and store in an airtight container. Ensure you allow it to fully defrost before serving.