Heat the oven to 170C/150C fan /gas 3 1/Put the cocoa powder,100g of the muscovado sugar and instant coffee in a large measuring jug. Pour over the boiling water and rum and whisk until smooth.
In a medium pan melt the butter and remaining sugar over a low heat. Add the dark chocolate and slowly melt together, stirring occasionally.
Once melted, pour the cocoa, the sugar and coffee mixture, eggs and vanilla bean extract into the jug and whisk until combined.
In a large mixing bowl sieve in the flour, bicarb and baking powder and spices, pour over the chocolate mixture and add a pinch of salt.
Gently whisk to form a smooth batter.
Divide this batter equally between approximately 20 muffin cases.
Bake in the centre of the oven for around 25 minutes.
When done they will smell chocolatey and a skewer inserted into the centre will come out clean.
For the dairy-free ganache/buttercream
In a pan bring the cream alternative and margarine to the boil, remove from heat add the chocolate and stir until combined.
Allow to cool.
Cream the margarine and icing sugar together then add the vanilla extract and cooled ganache.
Beat well until smooth and creamy.
Pipe or spoon onto the cooled muffins and top with cherry, strawberry or raspberry.
Note: The muffins texture and flavour improves if you can keep your hands off them for a couple of days!