Preheat oven to 350°. Grease a 9-in. springform pan and line the bottom with parchment; set aside.

In a small saucepan, heat beer and butter until butter is melted. Remove from the heat; whisk in sugar and cocoa until blended. Combine the eggs, sour cream and vanilla; whisk into beer mixture. Combine flour and baking soda; whisk into beer mixture until smooth. Pour batter into prepared pan.

Bake until a toothpick inserted in the center comes out clean, 45-50 minutes. Cool completely in pan on a wire rack. Remove cake from the pan and place on a platter or cake stand.

In a large bowl, beat cream cheese until fluffy. Add confectioners sugar and cream; beat until smooth (do not overbeat). Frost top of cake. Refrigerate leftovers.