Heat oven to 350 degrees F.

For a double layer cake, grease two 9" cake pans with butter, line with parchment paper; grease top of parchment paper with butter too.

In mixing bowl, whisk together flour and baking soda; set aside.

In small sauce pan, melt butter with Guinness on medium low heat. Remove from heat and whisk in sugar and cocoa powder until smooth.

In medium mixing bowl whisk together sour cream and eggs; stir in vanilla extract.

Once cooled, add Guinness mixture to sour cream mixture and whisk until smooth.

Slowly add flour mixture and stir until just blended. Pour equal amounts in cake pans.

Bake for about 25 minutes, or until toothpick comes out dry when inserted in the middle.

Let cool for about 15 minutes in pan, remove and cool on rack.

Optional: Slice each cake in half, horizontally, for a 4-layer cake.

For frosting, beat cream cheese and butter until fluffy, about 4 minutes. Add powdered sugar, one cup at a time until desired sweetness and consistency. Add cocoa, vanilla extract and beat until blended.

To make the cake, place first layer of cake on cake platter; spread generous layer of frosting. if making two layers, add the optional sliced strawberries. For a 4-layer, just repeat the first step.

and then add sliced strawberries. When finished with the layers, frost entire cake. For decorative layer, gently press Oreo cookie tops/bottoms into sides and top of cake. Refrigerate until ready to enjoy!