Preheat the oven to 350 F or 180 C and grease a 9 inch springform pan with butter.

In a saucepan, combine the butter and Guinness and place on medium heat, stirring every now and then until the butter is completely melted.

To the mixture, add the sugar and cocoa, stirring to combine.

In a small bowl, beat together the eggs, yogurt and vanilla. Add this mixture to the Guinness mixture.

Then, stir in the baking soda followed by the flour until everything is incorporated and bubbles begin to appear on the surface.

Pour the mixture into the prepared baking tin and bake for 45-60 minutes or until a toothpick inserted comes out with a few damp crumbs.

Let the cake cool completely before frosting.

Place the butter in a small saucepan over medium to low heat and let it melt and come to a boil. Swirl the pan, you do not need to stir it.

After 5-8 minutes, the butter should turn a light golden brown color- when specks appear on the surface, take the butter off the heat and pour into a bowl. Be extra careful not to burn the butter- it's better for it to be under browned than over brown and burnt. Don't scrape the saucepan, and you don't need to add all the butter as those specks left behind will take away from the smooth texture.

Let the butter cool slightly and then add the cream cheese.

Once the mixture is smooth, gradually beat in the powdered sugar until you reach your desired consistency. Add more if necessary.

Finally, beat in the vanilla.

Pour the frosting atop the cooled cake and spread with a butter knife or offset spatula.