The ganache is made first because it needs to set or firm up before being piped or spooned into the baked cupcakes.
To make the ganache, just heat the cream on a pan on the stove. Do not allow the cream to boil. Then turn off the heat and remove the pan from the stove, and place the chocolate into the heated cream. Whisk the chocolate and cream together until smooth and silky. Place it in the fridge while you make the cupcakes.
MAKING THE COFFEE CUPCAKES.
In a bowl whisk together the flour, cocoa powder, baking powder, baking soda and salt.
In a separate bowl combine and beat together the oil, sugar, eggs, vanilla extract & instant coffee granules.
When combined beat in half the flour mixture alternating with half the buttermilk. Repeat one more time until all the flour mixture and buttermilk has been added and well beaten and combined.
Turn off the mixer and scrape down the sides of the bowl as necessary.
Spoon the batter into the prepared pans, filling each cupcake liner about ⅔ full.
Bake in a preheated oven of 350°F / 180°C,for 15-20 minutes or until a skewer or toothpick inserted comes out clean.
Remove from the oven and allow the cupcakes to cool, while you prepare the buttercream
MAKING THE COFFEE BUTTERCREAM
Mix the coffee granules with the cream
In a bowl, beat the butter until fluffy.
Beat in the powdered sugar, the vanilla extract and coffee and cream mixture. If you find the buttercream too weak or runny, then add in more confectioners sugar a ¼ cup at a time, until it reaches the desired consistency.
ASSEMBLING THE CUPCAKES
I usually cut off the domes of the cupcakes when it has cooled completely. I find it creates a more level surface which makes it easier to pipe the frosting decoratively.
This is an optional step, if you prefer the rounded top of the cupcakes, then leave it as is and continue with the following step.
When the cupcakes are completely cool scoop out the centers of the cupcakes, but do not go all the way through them, you do not want the ganache to fall out.
Remove the ganache from the fridge, it will be very firm. Whip it with a hand mixer until it lightens in color and becomes fluffy and has a spreadable like consistency.
If you find that it is too firm to mix then place it on the stove for less than a minute, just to soften, making it easier to whip.
Do not keep it on the stove for longer than a minute or it will turn runny making it impossible to whip. If this does happen, then just place it in the fridge again to set and firm up before whipping.
Fill the scooped out center of each cupcake with the whipped ganache and pipe or spread over with the prepared buttercream. Decorate as desired.
Notes
1. If you do not have buttermilk, then just substitute it by adding 2 teaspoons of vinegar or lemon juice to ½ cup of milk.Leave undisturbed for 5 minutes before using.