Line a 20cm square tinwith baking paper, leaving a slight overhang on two sides so you can easily lift the fudge once it sets.
Add the sweetened condensed milk, brown sugar, unsalted butter, golden syrup, and glucose syrup to the mixing bowl. Cook for 7 min/100°C/speed 3 with the measuring cup removed and the simmering basket or splash guard in place.
Increase the temperature and cook for a further 12 min/Varoma/speed 3 with the measuring cup off and the simmering basket or splash guard in place.
Add the white chocolate and blend for 20 sec/speed 4. Scrape down the sides of the mixing bowl with a spatula, then blend again for 10 sec/speed 4 until smooth and melted.
Working quickly, pour the mixture into the prepared tin before it sets. Leave to cool on the benchtop for 20 minutes, then refrigerate for at least 6 hours, or overnight, before slicing into squares.
Wash the Thermomix bowl as soon as possible so any mixture stuck to the bottom doesn't harden.
Notes
Sweetened condensed milk: Nestlé and supermarket brands both work well in this recipe. Don't use evaporated milk - the fudge won't set properly.White chocolate: White chocolate melts (from the baking aisle) work best, as they're designed to melt smoothly. I've also tested Lindt white chocolate with good results.Storage: Keep your fudge in an airtight container in the fridge - it will stay fresh for up to 10 days. For longer storage, wrap each piece in plastic wrap or foil, then place it in a sealed container or freezer bag. Freeze for up to 3 months.