Guinness Chocolate Cake with Irish Buttercream

Guinness Chocolate Cake with Irish Buttercream features an easy, fudgy, and moist cocoa cake with Guinness beer and thick creamy and sweet Irish cream buttercream. The perfect St. Patrick’s Day cake!

Yield: 10 servings     Prep Time: 45 minutes     Cook: 40 minutes

This recipe involves chocolate AND booze. It doesn’t get much better than that.

What better way to celebrate St. Patrick’s Day? Or just any day, really. Because some days require chocolate & beer. And that might be because you’re celebrating something great… or because it’s been a long day.

The cake component of this recipe is super simple. You don’t even need an electric mixer! So you only have to clean your stand mixer bowl once (for the frosting).

The cake base contains sour cream to give the cake a ton of richness and moisture and the Guinness beer as the liquid to give it that kind of deep, roasted, slightly coffee-like taste that pairs so wonderfully with chocolate.

Feel free to get creative with decorating this cake! We went for a ‘naked’ look where the sides of the cake peek through the frosting. That focuses the attention on that drippy chocolate topping. You could go crazy with green food coloring, shamrock sprinkles, or gold coins for a festive look.

Or keep it classic with chocolate shavings or even a drizzle of salted caramel for an extra tasty garnish.

How to Make Guinness Chocolate Cake with Irish Buttercream

How to Make MOIST Cake

Be very careful not to accidentally over-measure the flour and cocoa powder in this recipe. This will lead to dense, dry, or tough cake. The best way to ensure this never happens is to measure your ingredients by weight using a digital kitchen scale. This will forever improve your baking!

If you don’t have one, then use the spoon and level method to measure your dry ingredients.

How to Prevent Your Chocolate Cake from Sinking

Make sure your oven is at the correct temperature, your baking powder & soda are fresh, and that you’ve measured all ingredients properly. Avoid over-mixing the batter. Bake the batter soon after mixing it up (don’t let it sit for hours). Bake in the center of your oven and don’t open the oven door unnecessarily. Lastly, don’t underbake the cake. A cake tester or toothpick should come out clean!

This is an extremely moist and rich cake recipe, so if your cake does sink slightly in the center don’t worry. It’s definitely not ruined! Simply use a serrated knife or cake leveler to level off the cake for a flat layer.

Perfect Bailey’s Irish Cream Buttercream

Be sure your butter is completely at room temperature so it blends into a smooth buttercream icing. Also be sure to use finely ground powdered sugar. Not sure if you’ve got the right sugar? Check out my post on 6 Secrets to Perfect Buttercream.

Whatever you do, don’t skip sifting the sugar!! Otherwise you will end up with unattractive lumps. If you’d prefer to keep this recipe free of any un-cooked alcohol, feel free to replace the Irish Cream with regular cream.

Can I bake this with different sized baking pans?

Probably! You’ll just need to do a little math to adjust the timing and calculate the volume. Check out Wilton’s handy guide for converting cake baking pans.

How to Make Cake Ahead of Time

You can wrap unfrosted un-cut cooled cake layers completely in several layers of plastic wrap. Place inside a freezer bag. Store at room temperature for up to 4 days or freeze for up to 2 months. Defrost overnight in the fridge (do not defrost at room temperature or you will end up with mushy cake).

How to Store Frosted Cake

Since frosting acts as a protective seal that keeps the cake moist and fresh, frosted cakes can be stored at a cool and dry room temperature for 2 to 3 days. Especially this frosting since it has some alcohol content to further preserve. Cover with a cake keeper to keep the frosting and decorating intact. Don’t use plastic wrap, which will not only ruin your frosting but also create condensation that can cause the frosting to separate.

Ingredients

For the Guinness Chocolate cake:

• 1 3/4 cups (222 grams) all-purpose flour
• 2 cups (400 grams) granulated sugar
• 3/4 cup (64 grams) unsweetened cocoa powder
• 2 teaspoons baking soda
• 1/2 teaspoon baking powder
• 1 teaspoon fine salt
• 3/4 cup (170 grams) sour cream or plain full fat yogurt
• 1/2 cup fresh vegetable oil
• 3 large eggs, at room temperature
• 1 teaspoon vanilla
• 1 cup Guinness beer

For the Irish Buttercream:

• 4 sticks (454 grams) unsalted butter, at room temperature
• 6 cups (750 grams) powdered sugar, sifted
• 1/4 cup plus 2 tablespoons Irish cream, 

For the chocolate drip:

• 4 ounces (113 grams) semisweet or bittersweet chocolate, finely chopped
• 1/2 cup heavy cream

Directions

Make the cake:

1. Preheat the oven to 350°F. Generously grease two 8-inch cake pans and line with parchment rounds.
2. In a large mixing bowl, whisk together the flour, sugar, cocoa, baking soda, baking powder, and salt.
3. In a medium bowl whisk together the sour cream, vegetable oil, eggs, vanilla, and beer.
4. Add the wet ingredients into the dry ingredients and stir with a spatula until just combined.
5. Divide the batter between the prepared pans and bake for 35 to 40 minutes, or until a cake tester comes out clean. Cool the cakes in their pans for 30 minutes before carefully turning them out onto a cooling rack to cool completely. If possible, freeze the cakes while you prepare the buttercream.

Make the buttercream:

1. In a large bowl, use an electric mixer to beat the butter until light and fluffy. Gradually add the powdered sugar then the Irish cream. Beat the mixture on high speed until very light, fluffy, and smooth, about 3 minutes. If the frosting is too thick, add a splash more Irish cream. If it’s too thin, add some more powdered sugar.
2. Assemble:
3. Place one cake layer a cake stand or serving plate. Frost the top of the cake generously, as this will become the filling. Use even more if you're decorating as a 'naked' cake as shown in the photos. Top with the other cake layer, flat side up.
4. With an offset spatula, spread a very thin layer of frosting all over the cake. This layer is a crumb coat and should act like spackle. For the smoothest frosting, return the cake to the fridge or freezer until firm to the touch. 
5. Spread the remaining frosting all over the cake. If desired, focus the frosting on the top to maintain the 'naked' look. Refrigerate while you prepare chocolate drip.

Make chocolate drip:

1. Place the chopped chocolate in a heatproof bowl. Bring the heavy cream to a simmer then immediately remove from heat and pour over chocolate. You can also do this in the microwave. Cover for a few minutes then stir until smooth.
2. Allow to cool until it has thickened but is still pourable, about 10 minutes. Don’t place ganache in the fridge to cool. Test the consistency of the drip by pouring down the side of a glass. If it’s too thick, microwave for 5 to 10 seconds. If it’s too thin, allow to continue to cool.
3. The cake can be stored, covered, at room temperature for up to 1 day or in the fridge for up to 3 days.