This is the dark, fudgy, deeply chocolatey cake made with a full bottle of Guinness — the stout’s roastiness amplifies the cocoa flavor without leaving any beer taste. Frosted with a Bailey’s Irish cream buttercream that’s billowy and pale against the espresso-dark crumb. The St. Patrick’s Day showstopper, honestly good year-round.
Fun fact: stout cakes were a way for Irish home bakers to stretch expensive cocoa during World War II — the dark beer added color and depth so you needed less actual chocolate. The original recipes had no chocolate at all, just cocoa and Guinness. The version with melted chocolate folded in (like this one) came later, after rationing ended.
Why this recipe works
GUINNESS = CHOCOLATE AMPLIFIER. Stout’s roasted barley shares flavor compounds with dark chocolate. It tastes like chocolate, not beer. The alcohol bakes off.
MELT BUTTER INTO BEER. Heating butter into Guinness creates an emulsion that gives the cake a glossy, fudgy crumb — like a brownie-cake hybrid.
SOUR CREAM TENDERIZES. The acid plus fat keeps the crumb tender and moist for 4+ days. This cake actually gets better on day 2.
Ingredients
Serves 12.
Cake:
1 cup Guinness stout (or other dark beer)
1 cup unsalted butter
3/4 cup unsweetened cocoa powder (Dutch-process preferred)
2 cups granulated sugar
3/4 cup sour cream, room temperature
2 large eggs, room temperature
1 tbsp vanilla extract
2 cups all-purpose flour
2 1/2 tsp baking soda
3/4 tsp salt
Irish cream buttercream:
1 cup unsalted butter, softened
4 cups powdered sugar
1/4 cup Bailey’s Irish cream
2 tbsp heavy cream
1 tsp vanilla extract
Pinch of salt
Optional garnish:
Cocoa powder for dusting
Chocolate shavings
Gold-dust flakes for St. Pat’s special
Instructions
Step 1: Prep pans + oven
Preheat oven to 350°F (175°C). Grease two 9-inch round cake pans and line bottoms with parchment paper rounds.
Step 2: Make the wet base
In a saucepan, heat Guinness and butter over medium-low until butter melts. Off heat, whisk in cocoa and sugar until smooth. Let cool 5 minutes — you don’t want to cook the eggs.
Step 3: Whisk in eggs and sour cream
Whisk in sour cream, eggs, and vanilla until smooth and glossy.
Step 4: Fold in dry ingredients
In a separate bowl, whisk flour, baking soda, and salt. Sift into the wet mixture in 2 additions, whisking just until combined. Don’t overmix — small lumps are fine.
Step 5: Bake
Divide batter evenly between pans. Bake 32-38 minutes until a toothpick inserted in center comes out with just a few moist crumbs. Cool in pans 10 minutes, then turn out onto a rack to cool COMPLETELY.
Step 6: Make the buttercream
Beat butter with electric mixer 3 minutes until pale and fluffy. Add powdered sugar 1 cup at a time, beating between. Add Bailey’s, heavy cream, vanilla, salt. Beat on high 2 more minutes until silky.
Step 7: Assemble
Place one layer on a cake stand. Spread 1/3 of frosting on top. Add second layer. Frost top and sides with remaining frosting. Dust with cocoa powder. Slice with a hot dry knife for clean cuts.
Nutrition information
Calories: 580 kcal per serving
Protein: 5 g
Carbohydrates: 76 g
Sugar: 58 g
Fat: 28 g
Saturated Fat: 17 g
Pro tips for the best guinness chocolate cake
USE DUTCH-PROCESS COCOA. Darker color, smoother flavor, less acidity. Natural cocoa works but the cake will be lighter and slightly more tart.
ROOM TEMP DAIRY. Cold sour cream + cold eggs = lumpy batter. Pull dairy out 1 hour before baking.
Bake AHEAD. This cake is actually better on day 2 — flavors meld and crumb tightens. Bake unfrosted, wrap tight, frost day-of.
Non-alcoholic version: Sub Guinness for strong brewed coffee + 1 tsp baking soda. Sub Bailey’s for 1/4 cup heavy cream + 1 tsp Irish cream extract.
Frequently asked questions
Can I taste the beer?
Honestly no. It tastes like deep chocolate. Even non-drinkers don’t pick up beer flavor. The alcohol bakes off.
Does Bailey’s bake off too?
Bailey’s stays raw in the buttercream — there IS alcohol in the frosting. Use the non-alc swap if serving kids or pregnant guests.
Can I make cupcakes?
Yes — fill liners 2/3 full, bake 20-22 minutes. Makes 24 cupcakes. Frost with the same buttercream.
Why is my cake sunken?
Either overmixed batter or you opened the oven before 25 minutes. Both kill rise. Mix gently, peek through the window only.
How long does it keep?
4 days at room temp (covered cake dome). Don’t refrigerate — it dries out the crumb. Freeze unfrosted layers up to 3 months, frosting separately.
