Place the chopped chocolate in a heat proof bowl. Heat 200ml (a little less than a cupful) of cream in a saucepan along with the strong black coffee (or coffee extract) and pour this over the chocolate and stir till the chocolate has melted. Leave to cool for 30-40 minutes (or until the ganache is thick enough to be spread without dripping)

Whip the rest of the double cream till firm peaks are formed (do this after the pies are baked and you are ready to assemble them)

Preheat the oven to 180 degrees C. Line 2-3 large baking sheets with baking parchment. Sift the flour, baking soda and salt together into a bowl.

In another bowl beat the butter and sugar till it fluffy. Beat in the egg. Add in the flour mixture and the buttermilk in parts until well incorporated.

Divide the batter into two bowls. To one bowl add the vanilla extract and to the other bowl stir in the strong coffee (or coffee extract) and cocoa  and mix well.

Mix the two batters into a single bowl very lightly (till you just see a marbled effect - don't over mix as the brown will take over completely leaving you with no marble effect)

Using a tablespoon place 20 mounds of the mixture onto the baking sheets, spaced well apart. Make sure that you place equal amounts of batter as you will get fairly even sized pies which will help while sandwiching them.

Bake in the preheated oven for about 10-12 minutes until the pies have just risen and are firm to the touch. Remove and cool for 5 minutes before transferring to a wire rack to cool completely.

Spread the chocolate mixture on the flat side of a pie and top it with the whipped cream. Cover with another pie.

Repeat the process till all the pies have been sandwiched using the two types of filling.

Serve immediately