Line a 20 cm square cake tin with baking paper and put to one side for now.
Place a heavy based saucepan over a medium heat and add the butter and cocoa powder. Stir together until combined and smooth. Immediately remove from the heat and add the chocolate stirring until it has melted.
125 g unsalted butter, 20 g cocoa powder., 100 g chocolate
Add the crumbled biscuits and stir to combine.
250 g digestive biscuits
Transfer the mixture in the lined cake tin and press firmly to compact. Put to one side until needed.
Making the caramel is easy. Add the butter, sugar and condensed milk into a saucepan over a low-medium heat and heat very gently until the sugar has melted.
100 g unsalted butter, 100 g muscovado sugar, 400 g condensed milk
Turn the heat to a medium high and continue to stir while the mixture starts to boil. As soon as its boils, reduce the heat to low and continue to stir until the mixture has thickened. Normally 5 – 8 minutes.
Once thickened, pour over the base in the lined tin and leave to cool.
Now for the top layer. Place a saucepan of water over a medium heat. Once hot, place the chocolate in a bowl over the water, but not touching it and Add the chocolate.
200 g chocolate
Stir the chocolate until fully melted and then pour it over the caramel in the lined tray.
Put the tray to one side to cool fully. When your ready to cut the millionaires shortbread use a warmed sharp knife.