Preheat the oven to 325 F (163 C). Lightly grease and line the bottom of (1) 8 inch cake pan with parchment paper. In a large bowl, whisk the all purpose flour, dutch process cocoa powder, baking powder and salt until well combined.
1 cup (120 g) all purpose flour, 6 tablespoon (30 g) dutch processed cocoa powder, 1½ teaspoon baking powder, ½ teaspoon salt
In another large bowl add the melted butter, oil, granulated sugar, eggs, vanilla extract and sour cream. Mix until smooth and well combined.
¼ cup (59 ml) oil, ¼ cup (57 g) unsalted butter, melted, 1 cup (200 g) granulated sugar, 1 large egg (US), room temperature, 1 teaspoon (5 ml) vanilla extract, ½ cup (120 g) sour cream, room temperature
Slowly mix the dry ingredients into the wet, alternating with the warm coffee until wet until smooth and well combined.
½ cup (118 ml) very warm coffee or water
Pour the chocolate cake batter into the prepared cake pan. Bake the cake for about 35 - 45 minutes.Cool the cake in the pan for 15 minutes then carefully remove the cake from the pan to cool completely. While the cake cools, make the chocolate ganache frosting. Pour the chocolate chips or chopped chocolate into a mixing bowl. Heat the heavy cream to a very light simmer either in a small sauce pan over low heat or by heating the cream in the microwave for 30 - 45 seconds.
1 cup (6 oz, 170 g) semi sweet or dark chocolate chips or chopped chocolate, 6 oz. heavy cream
Pour the heavy cream over the chocolate and allow the chocolate to melt for about 3 minutes. Using a spoon or spatula, gently mix the heavy cream and chocolate until the chocolate has fully melted into the cream. Allow the ganache to fully cool until it’s become more like a soft fudge like consistency. If you would like more of a silky ganache topping for the cake, feel free to top the cake at this point or right after the ganache is fully mixed. Once the chocolate ganache has fully cooled and thickened, whip the ganache on medium-high speed for 3 - 4 minutes until lightened and increased in size.
Evenly spread the chocolate ganache cake with the whipped ganache topping. Use the back of a small spoon to create some decorative swirls and swoops if you like!