Guinness Chocolate Cake with Irish Buttercream

You want a chocolate cake that tastes like a cozy pub hug and looks like you actually tried? Me too. I fell hard for this Guinness Chocolate Cake with Irish Buttercream the first time I made it, and I kept sneaking slices while nobody looked. This cake balances rich chocolate with a little stout swagger, and the buttercream? It adds that boozy-sweet finish that makes everyone ask for seconds.

If you like desserts with personality, you’ll love this one. I even linked a similar cozy dessert I make when apples are in season — check out my take on Irish apple cake with custard sauce for another crowd-pleaser. Ready to bake something impressive but not dramatic? Let’s go.

Why You’ll Love This Recipe

• Deep chocolate flavor thanks to the Guinness mixing with cocoa for a richer taste than plain water or milk.
• Moist, tender crumb from the sour cream and oil combo — no dry cake regrets here.
• Buttercream with a twist: Irish cream liquor gives the frosting a grown-up, velvety edge.
• Easy pantry-friendly ingredients — no weird gadgets, just good old baking staples.
• Great for celebrations or casual Sundays — it looks fancy but doesn’t require pastry-school skills.

Ingredients You’ll Need

Here’s everything you need, laid out so you can toss it in your cart and call it a day:

• 1 cup Guinness beer
• 1 cup unsweetened cocoa powder
• 1 3/4 cups all-purpose flour
• 2 cups granulated sugar
• 1 1/2 teaspoons baking powder
• 1 1/2 teaspoons baking soda
• 1 teaspoon salt
• 2 large eggs
• 1 cup sour cream
• 1/2 cup vegetable oil
• 1 teaspoon vanilla extract
• 1 cup unsalted butter (for buttercream)
• 4 cups powdered sugar (for buttercream)
• 1/4 cup Irish cream liqueur (for buttercream)
• 1 teaspoon vanilla extract (for buttercream)

How to Make (Step-by-Step)

1. Preheat & prep the pans

Preheat your oven to 350°F (175°C). Grease and flour a 9×13 inch pan, or line and grease two 9-inch round pans. I prefer the 9×13 when I want leftovers—and I always want leftovers.

2. Mix Guinness and cocoa

In a large bowl, whisk together Guinness beer and cocoa powder until smooth. This step dissolves the cocoa and builds that deep, malty cocoa base. Ever wondered why stout works so well? It adds depth without tasting like beer.

3. Combine dry ingredients

In another bowl, whisk the flour, sugar, baking powder, baking soda, and salt until even. Then fold the dry mix into the Guinness mixture until combined and no dry streaks remain.

4. Add wet ingredients

Add eggs, sour cream, vegetable oil, and vanilla extract. Beat the batter until glossy and smooth. The sour cream keeps the crumb tender while oil guarantees the cake stays moist even days later.

5. Bake the cake

Pour the batter into the prepared pan(s) and bake for about 30–35 minutes, or until a toothpick comes out clean. Watch the oven at the 25-minute mark; ovens lie, but they also forgive if you check.

6. Cool completely

Let the cake cool fully before frosting. If you frost a warm cake, the buttercream melts into a sad puddle—trust me, I tested that theory multiple times.

7. Make the Irish buttercream

Beat unsalted butter until creamy. Gradually add powdered sugar, then stream in Irish cream liqueur and vanilla extract. Beat until fluffy and spreadable. Taste and adjust — add a splash more liqueur if you want that boozy kiss.

8. Frost the cake

Frost the cooled cake with the buttercream. Keep swirls or go smooth; both look great and both taste like guiltless indulgence.

9. Serve and enjoy!

Slice, plate, and accept compliments. Pair with coffee, more Guinness, or a smug smile.

Pro Tips for the Best Results

• Room temperature eggs mix better and give a smoother batter. Cold eggs? They’ll work, but they’ll make you sigh.
• Sift the cocoa to avoid lumps. Cocoa clumps hide like tiny saboteurs.
• Don’t overmix once flour goes in. Stop when you see no dry bits.
• Use full-fat sour cream — the low-fat stuff makes a less tender crumb.
• Chill your buttercream for 10 minutes if it feels too soft before spreading.
• Stabilize frosting: If your kitchen is warm, add more powdered sugar a tablespoon at a time until it holds shape.
• Consider a simple syrup (equal parts sugar and water, boiled and cooled) brushed on layers to keep them extra moist.

Fun Variations & Topping Ideas

Variations:

• Add 1/2 cup chocolate chips to the batter for pockets of molten joy.
• Fold in zest of an orange for a citrus-chocolate lift.
• Swap sour cream for Greek yogurt for a tangy twist (IMO, a tiny bit denser but still great).

Toppings:

• Crushed toasted hazelnuts for crunch and nuttiness.
• Shaved dark chocolate for drama.
• A light dusting of cocoa or powdered sugar if you’re feeling minimalist.
• Fresh raspberries for color contrast and tartness.

Storing and Reheating

• Room temperature: Keep the frosted cake covered for up to 2 days. Buttercream stays stable at room temp for a little while.
• Refrigerator: Store in an airtight container for up to 5 days. Bring slices to room temperature before serving for best texture.
• Freezer: Wrap slices tightly in plastic wrap and foil; freeze for up to 2 months. Thaw overnight in the fridge, then come to room temp.
• Reheating: Warm a slice for 10–12 seconds in the microwave to revive that just-baked feel. Don’t overdo it or you’ll liquefy the buttercream. FYI, a warm slice and cold ice cream = food therapy.

Leftover ideas

• Crumble leftover cake into an ice cream sundae for instant decadence.
• Make trifles: layer cake chunks with whipped cream and jam.
• Blitz cake crumbs with melted chocolate and press into tart shells for mini desserts.
• Toast small cubes in a pan to make quick crunchy croutons for dessert salads. Sounds wild, tastes great.

Frequently Asked Questions (FAQ)

Can I substitute another stout or beer?

Yes. You can use another stout or porter if you don’t have Guinness. The cake will taste slightly different, but it will still taste amazing. I tested with a porter and got a deeper caramel note.

Can I make this cake gluten-free?

You can swap in a 1:1 gluten-free flour blend, but expect a slightly different crumb structure. Use xanthan gum if your blend lacks it. I’ll be honest: texture shifts, but flavor doesn’t lie.

Is the Irish cream in the buttercream necessary?

Not necessary, but it elevates the frosting from “nice” to “memorable.” You can use milk or cream if you prefer to skip alcohol. The buttercream will taste sweeter and less complex.

Can I double the recipe for a taller cake?

Absolutely. Double the batter for three 9-inch layers or a larger sheet. Adjust baking time, and test with a toothpick. I double it for parties and never worry about leftovers.

How do I fix a grainy buttercream?

Beat longer on medium speed and let it rest for 5 minutes; the sugar dissolves and the texture smooths out. If that fails, slightly warm and rebeat, but don’t melt the butter.

Conclusion

This Guinness Chocolate Cake with Irish Buttercream hits that sweet spot between cozy and show-stopping. It uses simple ingredients, delivers intense chocolate flavor, and tops everything off with a silky, boozy buttercream that keeps people talking. Try it for holidays, birthdays, or when you just need chocolate to feel better. If you want a trusted recipe origin and extra tips, see Handle the Heat’s Guinness Chocolate Cake with Irish Buttercream for a great reference.

Drop a comment if you try this or if you have a twist I need to taste-test. Rate it so I know whether to keep hoarding this recipe like it’s a secret. Seriously, go bake it—then tell me how many slices you managed to hide. 🙂