Chocolate Guinness Cake with Baileys Irish Buttercream: Don’t doubt the power of beer in chocolate cake! The results are amazing! This is a deep, rich chocolate sheet cake that’s soft and tender under a layer of creamy and boozy Baileys Irish buttercream.

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

Eons ago, when this site was just a wee babe (or, you know, in 2010), I shared a recipe for Guinness chocolate cupcakes that made my heart grow just a little bit with every bite.

I had never considered baking with beer, no less a dark and moody stout, before. I’m not a beer drinker in the least so baking with beer was so far off my radar that I had trouble wrapping my brain around it.

I mean, beer? In a cupcake??

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

But I came across the idea after the internet was sent into a tizzy from some chocolate whiskey and beer cupcakes that were originally and infamously posted under the name of “Irish car bomb cupcakes.” That name has since been changed to protect the innocent but the powerful impact of the cupcakes remains.

They are phenomenal cupcakes! The chocolate flavor is deep and rich and the frosting is boozy and delicious. But as much as I loved them and for no apparent reason, I never made them again.

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

However, with St. Paddy’s Day approaching, I thought it might be fun to reboot that old chocolate Guinness cupcake recipe and help you all get ready to celebrate the luck of the Irish!

Chocolate Guinness Cake – A Sheet Cake with Some Oomph!

I’ve never been much of a sheet cake girl. To me, the mighty layer cake, with its extra layers of frosting, is what the cake gods meant for cake to be when it was dreamed up.

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

I mean, give me alllll the peanut butter frosting sandwiched between chocolate cake layers in this fudgy chocolate peanut butter cake! Or those perfect confetti cake layers with pure white vanilla confetti frosting in this Milk Bar birthday layer cake!

I seriously don’t know how some people don’t like frosting!

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

Layer cakes aren’t for everyone though, especially if you’re not a huge fan of frosting. So this Guinness sheet cake is just right for the people in your life who aren’t big on frosting.

The frosting layer is a more manageable one compared to what’s within and on top of a cake layer. But it’s what’s IN the frosting that gives this cake such a kick!

We’re talking Baileys Irish Cream here! It’s a boozy Irish cream buttercream frosting that pairs just right with the dark chocolate cake underneath.

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

And to make things interesting, I added a bunch of crumbled up chocolate wafer cookies to the top of those swoopy frosting swirls. Why not, right?? The cookie crumbles add some crunch and texture that I feel like cake sometimes needs without adding nuts, which I absolutely loathe as a cake ingredient.

Does Beer Bake out of Cupcakes and Cake?

Like many recipes that contain alcohol, the majority of the alcohol from the beer does bake out of the cake (or cupcakes if you’re making them). Not all of the beer bakes out, but most. What remains in the cake leaves a deeply flavored chocolate and a soft, moist, and tender crumb.

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

And if you’re weirded out by the idea of beer in your cake, have no fear! You cannot taste the beer whatsoever!

So, use your best judgement when you plan who you’ll be serving this cake to.

And because the Baileys in the frosting is not cooked at all, you’ll get the full effect of the alcohol in the frosting. Again, use your best judgement here.

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

How Many Servings in This Cake?

The cake itself is a substantial one. It bakes up high with a soft and tender crumb. And because it’s a super thick cake, you’ll benefit from getting extra servings out of it.

I cut the cake into 12 pieces and they were almost too much cake for a single serving. Almost. So, 15 squares would make more sense when serving this sheet cake.

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

How to Convert this Sheet Cake to Other Sizes

If you don’t need or want to make a sheet cake out of this recipe, you can certainly convert the cake into another size to suit your needs. Here are some suggestions for you!

To make cupcakes: Line 2 12-well muffin tins with cupcake papers and divide the batter evenly between the papers (two-thirds full). Bake at 350° F for 17 to 20 minutes.

To make mini cupcakes: Line 2 24-well mini muffin tins with mini cupcake papers and divide the batter evenly between the papers (two-thirds full). Bake at 350° F for 12 to 13 minutes.

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

To make a bundt cake: Grease a 10-inch bundt pan with baking spray or butter and flour. Pour the batter into the pan. Bake at 350° F for 50 to 60 minutes.

To make an 8-inch layer cake: Grease 3 8-inch cake pans with baking spray or butter and flour. Pour the batter into the pan. Bake at 350° F for 28 to 30 minutes.

To make a 9-inch layer cake: Grease 2 9-inch cake pans with baking spray or butter and flour. Pour the batter into the pan. Bake at 350° F for 30 to 35 minutes.

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

To make an 8-inch or 9-inch square cake: Cut the recipe below in half. Grease an 8-inch or 9-inch square baking pan with baking spray or butter and flour. Pour the batter into the pan. Bake at 350° F for 35 to 38 minutes for the 8-inch pan or 33 to 36 minutes for the 9-inch pan. Test with a toothpick in the center of the cake for both sizes – it should come up with just a couple tiny crumbs clinging to it.

If you want extra frosting on any of these cakes (except the 8- and 9-inch squares), increase the frosting recipe below by 1.5x.

More Suggestions for a St. Paddy’s Day Meal

If you’re looking to round out a menu for St. Patrick’s Day, our all-time favorite Irish meal is bangers and colcannon. It’s a copycat recipe I created from an Irish pub we found on a whim in Portland, ME.

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

Some Irish soda bread goes great with the bangers too!

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

Chocolate Guinness Cake with Baileys Irish Buttercream Frosting

Yield: 12 to 15 servings
Cake Prep Time: 20 minutes
Bake Time: 36 minutes
Frosting Prep and Assembly Time: 20 minutes
Total Time: 1 hour 16 minutes

Chocolate Guinness cake is the supreme level of dessert for your St. Paddy's Day celebration! The dark stout bakes into the cake, leaving it soft, moist, and tender, with a deep and rich chocolate flavor. Paired with a boozy Baileys Irish Cream buttercream frosting, this cake will surprise the most skeptical of your guests.

Ingredients

For the chocolate Guinness cake:

  • 1 cup Guinness stout (or another brand of stout)
  • 1 cup (2 sticks) unsalted butter, cut into 16 pieces
  • ¾ cup unsweetened Dutch-processed cocoa powder
  • 2 cups all purpose flour
  • 2 cups sugar
  • 1 ½ tsp baking soda
  • ¾ tsp table salt
  • 2 large eggs
  • ⅔ cup sour cream

For the Baileys frosting:

  • 3 cups confectioners' sugar
  • Pinch of table salt
  • 1 stick (½ cup or 4 oz) unsalted butter, at room temperature
  • 3 tbsp Baileys Irish Cream (or another brand of Irish cream liqueur)
  • 2 tbsp heavy cream

For the cookie topping:

Instructions

    1. To make the cake: Preheat oven to 350° F. Grease a 13x9-inch baking pan, line the bottom and sides with a large piece of parchment paper, and grease the paper. (A baking spray, like Pam for Baking, works great for this.)
    2. Bring the Guinness and butter to simmer in medium saucepan over medium heat. Add cocoa powder and whisk until mixture is smooth. Cool until the mixture is warm but not hot to the touch.
    3. In a large bowl, whisk the flour, sugar, baking soda, and salt until combined. In the bowl of a stand mixer fitted with the paddle attachment (or with a hand mixer in a large bowl), beat the eggs and sour cream together until well-blended. Add Guinness-chocolate mixture to egg mixture and beat to just combine the mixtures. At low speed, add the flour mixture until just barely combined. Using rubber spatula, fold the batter until the flour is completely combined. Pour the batter into the prepared pan and smooth out the top.
    4. Bake for 35 to 40 minutes, until a toothpick inserted into the center of the cake comes out clean. Transfer the pan to a wire rack and cool the cake for 10 minutes. Using the parchment paper, pull the cake out of the pan and allow it to cool to room temperature on the wire rack. Frost and serve immediately or wrap tightly in plastic wrap and refrigerate for up to 3 days before frosting.
    5. To make the frosting: Beat the butter in the bowl of a stand mixer fitted with the paddle attachment, or with a hand mixer, for several minutes, until light and fluffy. With the mixer on low speed, slowly add the powdered sugar. Once all the sugar has been added, scrape down the sides and bottom of the bowl with a silicone spatula and beat the frosting on medium speed for 1 minute. Add the Baileys and heavy cream and whip the frosting for 20 to 30 seconds, until well-combined.
    6. To assemble and serve: Place the cake back in the baking pan or on a large serving platter. Top with all of the frosting and using a long offset spatula, smooth the frosting out into an even layer, making swoopy swirls in it if you choose. Crumble the cookies into small pieces with your hands and sprinkle the cookie crumbs at 2 of the opposing corners of the cake (or in any other design). Slice the cake into 12 large or 15 smaller pieces.

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