Prepare a 9 inch by 9 inch square tin by lining it with parchment paper or thick tin foil.

In a stand mixer is the easiest way to make this slice, or you can a bowl and wooden spoon too. First, beat the butter and sugar together until they're fluffy and soft, then add the vanilla and salt and beat well. Meanwhile, break the plain chocolate into a heatproof bowl and melt in the microwave on 30 second increments, giving the mixture a stir after each 30 seconds.

Next, add the tin of condensed milk to the butter sugar mixture with the mixer running, and beat well - it will be a very wet mixture at this point. Pour in the melted chocolate and mix for a moment, then add the plain flour and mix well, using a spatula to scrape down to the bottom of the bowl and combine everything.

Scoop everything into your pan and flatten down with the back of a spoon.

Top with your Halloween sprinkles. Pop the pan into the fridge to set - for about an hour, or if you really are in a rush, in the freezer for 10 - 15 minutes.

Remove from the fridge 10-15 minutes before you want to serve it - it will be very firm, and use a large sharp knife to cut into squares. The mixture is VERY rich but I'm greedy, so my squares were massive.