Alcoholic Chocolate Freezer Cake

Crush the biscuits, almost to powder.
Add the booze to the biscuits.
For very soggy alcohol laden Christmas biscuits, use the full amount.
Slowly melt the butter.
Add the treacle and drinking chocolate powder to the melted butter.
Add the crushed biscuits to the melted butter mixture and stir well.
Flatten this mixture into a dish / dishes with a large area.
Compress the mixture well.
It should  be a bit thicker than a typical biscuit.
Melt the dark eating chocolate and spread it over the biscuit mix.
After spreading the melted chocolate, roughen the surface by stabbing it all over with a fork.
This helps the chocolate to stick to the biscuit layer.
Allow it to cool and set.
Before it becomes brittle, cut it up into slices. Freeze it.

                                   ===== Big =====     ===== Small =====  
Digestive biscuits (McVitie's work best)    1000 g           400 g
Butter                                       400 g           160 g
70% dark chocolate                           400 g           160 g
Drinking chocolate powder                    160 g            64 g
Distilled booze (optional). 
Rum, brandy or try others.         100 ml to 400 ml    40 to 160 ml
Black treacle                                 60 g            24 g