Spray your baking pan with non-stick cooking spray.
In a small saucepan, add the 1 cup Guinness Beer and 1/2 cup butter, and simmer until the butter is melted.
Remove from heat, and mix in the 2 cups granulated sugar and 3/4 cup baking cocoa. Add in the 2 large eggs 2/3 cup sour cream and 3 teaspoons pure vanilla extract Fold in the 2 cups all-purpose flour, 1 1/2 teaspoons baking soda, mix until smooth.
Pour your batter into the prepared pan.
Set the baking pan into the air fryer basket, and set the air fryer temperature to 320 degrees F, air fryer setting, and set cook time for 15-20 minutes.
Bake until a toothpick comes out clean, when placed into the middle of the cake.
While the cake is cooling. Make your frosting, add the 8 ounces cream cheese and 1 1/2 cup powdered sugar, and 1/2 cup heavy whipping cream, and mix.
Spoon over the cake and frost.