Preheat oven 180℃.
Sieve flour and cocoa powder into a small bowl, add baking powder and bicarbonate of soda, stir and set aside.
Warm milk (do not boil) over medium heat with a sauce pan, add coffee granulespowder stir to dissolve and combine, set aside to cool.
Cream butter, oil and sugar with an electric whisk on a medium mixing bowl until it becomes pale, light and fluffy.Add the egg and vanilla extractpaste, whisk until it is well incorporated.
Then add half of the flour mixture followed by half of the coffeemilk mixture, whisk until combined and repeat the process with the remaining ingredients, whisk until all the batter is well combined.Insert a muffin pan with standard cupcake cases, fill each with about two-thirds (2/3) of the batter.
Bake for 12 minutes or until a toothpick comes out clean when inserted. Leave the cupcakes to cool on the pan for 1o minutes. Then transfer all into a wire rack to cool completely.
Store the cupcakes in an airtight container for the next day. This recipe makes 15 cupcakes.
In a small sauce pan over medium-heat, heat double cream and sour cream until it just begins to simmer, add the chocolate and stir with a spatula until it has all melted.
Sieve it into a small mixing bowl, whisk (with a hand whisk) it a bit and allow to cool. After 30 minutes use a spatula to stir it again (do this process twice).
Leave the frosting to cool for an hour, and stir it again with a spatula (do this process twice). Cover the frosting with a lid or cling wrap, leave it to set overnight.