Pour boiling water into a small jug, add hot cocoa powder, and stir to dissolve. Pour into a shallower dish and set aside to cool until required.

To make chocolate ganache layer, place chocolate dotties in a medium bowl or jug. Heat cream in a small saucepan over medium heat until almost at boiling point, immediately pour over chocolate and leave for a couple of minutes to allow the chocolate to melt. Stir until smooth, set aside to cool slightly.

To make the mascarpone cream, in a large bowl, place mascarpone and vanilla extract and stir with a wooden spoon until smooth. In a separate bowl, using an electric mixer, beat cream and caster sugar until medium peaks form. Fold whipped cream into mascarpone in several additions, until fully combined.

To assemble the tiramisu, dip half of the ladyfingers quickly on both sides into the cooled hot cocoa. Place in a layer on the bottom of a 23cm square serving dish or cake tin. Spoon about a third of the mascarpone cream mixture on top and gently spread over the ladyfingers. Carefully pour over the chocolate ganache to cover the mascarpone layer as evenly as possible. Repeat with a layer of the remaining ladyfingers, quickly dipping in the cooled hot cocoa as you go. Pipe the remaining mascarpone cream on top. Top with a generous dusting of cocoa powder. Refrigerate for at least four hours to set, preferably overnight. Slice into squares to serve. 

Pour boiling water into a small jug, add hot cocoa powder, and stir to dissolve. Pour into a shallower dish and set aside to cool until required.

To make chocolate ganache layer, place chocolate dotties in a medium bowl or jug. Heat cream in a small saucepan over medium heat until almost at boiling point, immediately pour over chocolate and leave for a couple of minutes to allow the chocolate to melt. Stir until smooth, set aside to cool slightly.

To make the mascarpone cream, in a large bowl, place mascarpone and vanilla extract and stir with a wooden spoon until smooth. In a separate bowl, using an electric mixer, beat cream and caster sugar until medium peaks form. Fold whipped cream into mascarpone in several additions, until fully combined.

To assemble the tiramisu, dip half of the ladyfingers quickly on both sides into the cooled hot cocoa. Place in a layer on the bottom of a 23cm square serving dish or cake tin. Spoon about a third of the mascarpone cream mixture on top and gently spread over the ladyfingers. Carefully pour over the chocolate ganache to cover the mascarpone layer as evenly as possible. Repeat with a layer of the remaining ladyfingers, quickly dipping in the cooled hot cocoa as you go. Pipe the remaining mascarpone cream on top. Top with a generous dusting of cocoa powder. Refrigerate for at least four hours to set, preferably overnight. Slice into squares to serve.