Line a 20cm x 30cm baking tray or cake tin with baking paper.

Break or chop the white chocolate into pieces and place in a large microwavable bowl.  Pour over the condensed milk and mix together.

Pop the bowl into the microwave and heat in short bursts of around 30 seconds, taking it out and stirring in between, until the chocolate has almost melted.  Be very careful not to overheat.

Once the chocolate is just melted, add the vanilla extract and beat well with a wooden spoon until it all comes together smoothly.

Add a third of the sprinkles to the fudge mixture and quickly stir to combine.

Tip the fudge into the tin and spread around into an even layer.  Use a palette knife or spatula to smooth the top down.

Scatter the remaining sprinkles over the top of the fudge and press them gently into the top.

Pop the fudge into the fridge and leave to set for at least 2 hours or overnight.  Once the fudge has set hard, remove from the tin and cut into pieces.