• Grease a 9 x 13-inch (23 x 33cm) deep, baking pan & line base & sides with parchment paper, bringing the paper up over the sides.
• Combine the coffee, sugar, butter, cocoa & baking soda in a large saucepan or pot. Stir over medium heat until the butter is melted & sugar is dissolved. Increase the heat to medium-high & bring to a boil, taking care the mixture doesn’t boil over. Remove from the heat, pour into a large bowl (or you can mix it all up on one saucepan if it’s big enough to allow stirring & whisking) & let cool - about 20 minutes. Preheat the oven to 350F (180C).
• Once the mixture is cooled, add the sour cream & eggs; whisk until well combined. Add the flour & whisk until there are no lumps. Pour the mixture into prepared pan & gently bang the pan on the counter to remove some of the large air bubbles. Bake for 45 to 55 minutes or until a skewer inserted into the center comes out clean. Let cake stand for 10 minutes before removing to a wire rack to cool. Or cool in the pan if time permits.

To make the icing:

• Combine the butter, coffee & sugar in a medium saucepan. Stir over medium heat until the sugar is dissolved. Sift confectioner’s sugar & cocoa into the butter mixture. Use a whisk to remove any lumps. Pour into a bowl; cover & chill for 1 to 2 hours, stirring occasionally, until the mixture is thick & spreadable. If you make this ahead of time, leave out of the fridge for it to soften before you spread it on the cake, it needs to be a bit thicker than peanut butter.
• Spread the cold cake with the icing. Cuts into about 20 or so pieces.