Cake

1. Preheat the oven to 350F/180C and grease a 1lb loaf pan or  9" X 5" loaf pan heavily.
2. In a small bowl add the espresso powder and hot water and mix to dissolve the powder. Set aside to cool.
3. In the bowl of an electric mixer fitted with a paddle attachment or a large bowl with a handheld mixer beat the softened butter and sugar together on medium speed for 2 minutes or so, you want to really cream the mixture until its light and fluffy. Add in the eggs, one at a time, and beat until fully combined.
4. In a large bowl whisk together the flour, baking soda, baking powder, cocoa powder, and salt. In a liquid measuring cup or small bowl combine the whole milk, sour cream, and vanilla extract. 
5. Add half of the dry ingredients to the butter mixture and mix to just combine, then stir in half of the wet ingredients mixing until just combined, then repeat with the remaining ingredients.
6. Pour into the prepared pan and bake for 40-45 minutes, or until the cake is fully cooked. If you gently press the top middle of the cake it should bounce back immediately. Or if you stick a toothpick in the center of the cake it should come out with no wet batter. Let cool for 20 minutes on a wire rack then place a wire rack on top of the cake and flip over to invert the cake onto the wire rack to cool completely.

Frosting

1. In a small saucepan add the cream and cook over medium heat for a couple of minutes to warm it, you don't want to boil it though. 
2. In a large bowl add the chocolate and corn syrup then pour the warmed cream directly over it. Let it sit untouched for 5 minutes then using a whisk mix well together until a shiny homogenous chocolate ganache is formed. Store in the freezer for 20 minutes, I stir every 5 minutes or so, to chill the ganache and thicken it a bit.
3. Pour thickened ganache on top and spread into an even layer, let sit to set up for half an hour. Store the cake in an air-tight container at room temperature for up to 3 days. If you are in a very warm environment I would store it in the fridge but let sit at room temperature for 30-60 minutes before serving.