Guinness is a dark rich beer that lends itself to pair perfectly with chocolate. This Chocolate Guinness cake is rich and decadent especially with a smooth ganache drip running down the sides of the cake!
Preheat the oven to 350℉. In a stand mixer bowl combine all the dry ingredients and whisk it together. Place on the stand mixer with a whisk attachment on low speed.
Add the whole eggs and vegetable oil. Scrape down the sides of the bowl and the whisk attachment to make sure everything is being mixed properly.
Once the eggs and oil have been incorporated then add the buttermilk. Continue to scrape down the bowl.
Next, pour in the Guinness Extra Stout and gradually increase the speed to medium-high. Continue mix until the cake batter is smooth. Divide and pour cake batter into 3 - 6" prepared cake pans lined with cooking spray and parchment paper.
Bake in preheated 350℉ oven for 30-35 minutes. Check with a toothpick to make sure it's done.
Once done baking remove the cakes from the oven and set aside to cool. Allow to cool for 10 minutes, the cake pans should be cool enough to touch but still warm. Then carefully remove the cakes from the pan by turning the cakes upside and flip back upright and leave the parchment paper on the bottom to finish cooling. See notes if the cakes are sticking to the sides of the pan.
After the cakes have cooled completely, wrap in plastic wrap and freeze for 30 minutes. At this stage, you can cover the cakes and leave them in the freezer for several days or up to a month before decorating them.
In a stand mixer bowl, add the unsalted room temperature butter. Mix on medium-high until the butter is light in color and fluffy. Stop the mixer every few minutes to scrape down the sides of the bowl to make sure all the butter is well blended. This step can take up to 5 minutes and is essential to whipping air into the butter, so your buttercream is the creamy smooth texture we want.
Once the butter is light in color and fluffy, continue to mix on medium and add the vanilla extract and salt. Scrape down the sides of the bowl again before moving to the next step.
Then gradually add half of the sifted powdered sugar to the butter mixture. Next, add the heavy cream. Scrape down the sides of the bowl and especially the center of the bowl to make sure all the powdered sugar is getting incorporated.
Finally, add the last half of the powdered sugar and dark chocolate cocoa powder mix on medium-high. Continue to mix and scrape down the sides of the bowl until you don't see any more powdered sugar or cocoa powder. Then gradually add the Guinness stout. Continue to mix until you have a creamy and smooth buttercream.
The chocolate Guinness buttercream is ready to use. Fill a pastry (piping) bag with the buttercream for frosting a cake.
Place the chocolate chips into a medium bowl, set aside.
Heat the heavy cream in the stove top or in a microwave until it's hot but not scolding. Pour the hot cream over the chocolate chips let it steep and melt the chocolate chips. Use a rubber spatula to mix and combine the chocolate and cream.
Mix until all the cream is incorporated, smooth and glossy. If there’s still chocolate chunks, heat in the microwave gently for 15 seconds at a time until the ganache is smooth and glossy.
Place the smooth ganache in a squeeze bottle to make the drip lines. If it becomes too cold, then heat up the bottle of ganache in the microwave 15 seconds at a time. Be careful you don't want it to get too hot or else the drip lines will slide down the cake.
Remove the chilled cakes from the freezer and carefully slice the top of any dome of the cakes off to make them level and flat. This makes the stacking process much more manageable.
Next is decorating, use an offset spatula for layering the frosting in between each cake layer. Continue to a crumb coat, so the whole cake is covered then chill in the fridge for 20 minutes until the crumb coat has set.
Next, add a thicker layer of frosting onto the cake for the final coat. This is where you make the edges smooth and pretty. Place the cake back in the fridge for another 20 minutes to firm up the frosting before adding the ganache drip lines.
Now its time to make ganache drip lines. Use the slightly warmed ganache squeeze bottle and start at the top of the cake right at the edge. Then squeeze the ganache, so it runs down the side of the cake. Use different pressure to create the variable in the drip lines down the cake.
Finally, add swirls of chocolate Guinness buttercream on top and add mini chocolate chips! Now you have a rich, decadent Chocolate Guinness Cake that’s ready for St. Patrick’s Day or any weekend celebration!
This recipe makes enough for 3 (6”) cake layers but if you want to make this cake in larger cake pans, simply double the recipe to make 3 (8” or 9”) cake layers.
If the cakes are sticking to the cake pans, carefully run an off-set spatula or a small knife around the edges of the cake then flip the cakes out of the pan. That should release the cake from the sides of the pan.
For later use of the buttercream store in airtight containers and store in the refrigerator for up to 2 weeks. When you’re ready to use the Chocolate Guinness Buttercream, place it on the counter to come back up to room temperature. Then mix it on medium-high to make it smooth and creamy once again.