This insanely delicious and totally moist Guinness Chocolate Cake is topped with a thick layer of perfectly sweetened Irish whiskey buttercream frosting. It's made in only one bowl and is totally foolproof. The cake also happens to be vegan – but don't make it (or not make it) because of that. Make it because it's the best chocolate cake ever.

Sheet pan Guinness chocolate cake with Irish whiskey buttercream frosting on a blue marbled background.

Raise your hand if you want a slice of Guinness chocolate cake!

(I see a sea of waving hands from coast to coast.)

That chocolate Guinness cake you see up there isn't any ordinary cake; it's the best dang chocolate cake there ever has been. ← Truth

It's no small claim, but I've had enough votes on it to know for sure it's a winner. It's super rich in flavor, perfectly sweetened, ultra moist, and totally dreamy.

It's also made without eggs and uses oil instead of butter so it's naturally vegan. If you are too, that's awesome! If you're not (like me) then don't let that throw you off. Just make the cake exactly as is and forget all about me telling you it's vegan. Deal?

Close up picture of a slice of Guinness chocolate cake with lots of Irish whiskey buttercream frosting.

Now that thick layer of Irish Whiskey Frosting, on the other hand. That has delicious salted butter in it. BUT … I've used store-bought vegan margarine in the past when making frosting for vegan friends and it works surprisingly well. If butter is not your thing, pass me all the butter and I'll hand you all the Earth Balance. It'll work great in this recipe.

Also, let's pour a mug of Guinness and cheers to St. Patrick's Day and all the excuses to dig into a giant slice of Guinness Chocolate Cake.

There's an entire tall can of Guinness in that cake batter you see down there. ↓↓ It's what makes the cake crazy moist. The beer also helps bring out the flavor of the chocolate so the cake is extra rich in flavor.

Since Guinness is only ever sold in packs of four cans (at least it is here in Vancouver) then you'll have three more cans to drink. If you can spare one or two of those cans, try this Chocolate Guinness Crock Pot Beef Stew or this Guinness Spiked Irish Chili. Then bake a loaf of this Easy Whole Wheat Irish Soda Bread and finish the whole amazing St. Patty's Day themed meal with this Guinness Chocolate Cake. ☘

Chocolate cake batter being poured into a cake pan with cocoa powder dusted on it.

Just out of the oven sheet pan Guinness chocolate cake on a cooling rack with Irish whiskey buttercream frosting spread over part of the cake and a wooden spoon.

Close up of slices of Guinness chocolate cake topped with Irish whiskey buttercream frosting.

A close up picture of a slice of Guinness chocolate cake and a fork with cake on it.

If you love this One Bowl Guinness Chocolate Sheet Cake as much as I do, make sure to give it a 5-star review in the comments below!

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This insanely delicious and totally moist Guinness Chocolate Sheet Cake is topped with a thick layer of Irish whiskey buttercream frosting. It's made in only one bowl and is totally foolproof. The cake also happens to be vegan - but don't make it (or not make it) because of that. Make it because it's the best chocolate cake ever.  | theendlessmeal.com | #cake #chocolatecake #irishrecipes #veganrecipes #stpatricksdayrecipes #guinness

One Bowl Guinness Chocolate Cake with Irish Whiskey Frosting

  • Author: Kristen Stevens | The Endless Meal
  • Prep Time: 15 mins
  • Cook Time: 30 mins
  • Total Time: 45 minutes
  • Yield: 12 large slices 1x

Description

This insanely delicious and totally moist Guinness Chocolate Cake is topped with a thick layer of Irish whiskey buttercream frosting. It's made in only one bowl and is totally foolproof. The cake also happens to be vegan – but don't make it (or not make it) because of that. Make it because it's the best chocolate cake ever.


Scale

Ingredients

Guinness Chocolate Cake

  • 1440ml can of Guinness
  • 2 cups flour
  • 2 cups sugar
  • 3/4 cup cocoa powder, plus a little extra for the pan
  • 2 teaspoons baking soda
  • 2 teaspoons baking powder
  • 1 teaspoon salt
  • 1/2 cup neutral-flavored oil
  • 2 teaspoons vinegar
  • 1/2 cup chocolate chips

Irish Whiskey Buttercream

  • 1/2 cup softened butter (use vegan, if needed)
  • 1 1/2 cups powdered sugar
  • 1 1/2 tablespoons Irish whiskey

Instructions

  1. Preheat your oven to 350 degrees. Grease a 11×9 inch baking sheet with butter or coconut oil then sprinkle some cocoa powder over the top. Shake the baking sheet so the cocoa powder covers the butter.
  2. Pour half the can of Guinness into a small pot and bring it to a boil over high heat. Set the pot aside.
  3. While the Guinness is heating, make the rest of the cake. Whisk the flour, sugar, cocoa powder, baking soda, baking powder, and salt together in a large bowl. Add the oil, vinegar, and the remaining Guinness in the can and whisk. Pour the hot Guinness into the bowl and carefully whisk it into the batter. Stir in the chocolate chips.
  4. Pour the batter into the prepared baking sheet and bake in the oven for 25-30 minutes, or until a toothpick inserted into the middle of the cake comes out clean. After 10 minutes, remove the cake from the baking sheet and let it cool completely on a cooling rack. Once it is completely cool, cover it with the frosting.

Irish Whiskey Buttercream

  1. Place the butter, powdered sugar, and Irish whiskey in a large bowl. Cream together using electric beaters. For a thinner frosting, use more whiskey.