Add the chocolate chips or the chopped chocolate slab to a large heatproof bowl.
Add the heavy cream to a medium saucepan set over medium heat, and allow the cream to warm until just before boiling.
Pour the heated cream over the chocolate and allow the mixture to sit for about 2 minutes before stirring with a rubber spatula. Once stirred all the chocolate should’ve melted and the mixture should be smooth.
Place a piece of plastic wrap over the melted chocolate mixture, and ensure the plastic makes contact with the surface of the chocolate mixture. Allow the ganache mixture to set for about 6 hours in the fridge.
Chocolate Cupcakes
Preheat the oven to 180°C (350°F) and line 2x 12-hole cupcake pans with cupcake liners.
Add the butter, oil, and sugar to a bowl of an electric mixer fitted with a paddle attachment. Beat until light and fluffy.
Add the eggs to the sugar and butter mixture one at a time. Beat well between each addition and scrape down the sides of the bowl often.
In a large bowl sift together the flour, salt, and cocoa powder.
In a jug mix together the cooled coffee, sour cream, milk, and vanilla.
With the mixer’s motor running at medium-low speed, add the wet ingredients and the flour mixture to the egg and sugar mixture. Do this by alternating between the two. Starting with the flour and ending with the wet ingredients.
Using a rubber spatula scrape down the sides of the bowl and mix the cake batter again. Ensuring that it is well-mixed and lump-free.
Using a jug or ice-cream scoop pour the chocolate cupcake batter into the prepared cupcake liners and bake in a preheated oven for about 15 minutes or until a skewer inserted into the center of a cupcake comes out clean.
Allow the cupcakes to cool in their tin for about 5 minutes before transferring them to a wire rack to cool completely.