Prep your cake pan by spraying liberally with non-stick baking spray, then a light dusting with cocoa powder.
Set to the side.
In a medium saucepan, add the stout, coffee, and butter.
Heat over medium, stirring often until butter melts.
Add in the cocoa powder and mix until smooth.
Set the mixture to the side and allow to cool to room temperature.
In a medium bowl, whisk flour, sugar, baking soda, and salt.
In a stand mixer, add your eggs and sour cream.
Beat on medium until combined.
Reduce the speed to low and add the chocolate beer mixture.
Mix until well combined.
Begin to add flour mixture in 1/3 rds.
Beat on low until combined.
Pour the batter into your springform pan.
Cover the top and bottom of the springform pan with aluminum foil. The top will prevent water from getting into your cake, and the bottom will prevent leaks.
Place a triviet in your Instant Pot.
Add 1/2 cup water to the Instant Pot.
This will prevent the dreaded “Burn” warning.
Lower the cake into the Instant Pot on the trivet.
Seal and cook on high pressure for 35 minutes, then vent immediately.
Let the cake cool.
Place the ganache in the microwave for 45 seconds, heat until melted.
Pour the ganache over the top of the cake.
Set to the side.