Chocolate Guinness Snack Cake
A simple, two-bowl sheet cake flavored with rich cocoa powder and Irish Guinness stout. This Chocolate Guinness Snack Cake is the perfect way to celebrate St. Paddy’s season – or a great way to enjoy baking with your favorite stout beer year-round.

Chocolate Guinness Snack Cake
St. Paddy’s day is right around the corner, and I can’t think of a better way to celebrate our Irish friends than with an easy chocolate cake loaded with Guinness stout. I spent a month on the coast of Northern Ireland after college, and Guinness was definitely the drink of choice for the locals socializing at the pub. What they say is true: Guinness does taste better on the Emerald Isle. But I think this Guinness cake does the beer justice and is sure to be enjoyed by any chocolate cake fan…even if our Guinness comes from a can 😉
This cake comes together similarly to a boxed cake mix. Once you have the Guinness reduced, the process of mixing the dry ingredients and then the wet, and finally combining the two is pretty simple. And since the Guinness flavor isn’t strong in this cake (it mainly enhances the cake’s chocolate flavor) any chocolate cake fan should enjoy a slice of this Guinness Chocolate Snack Cake. In other words, you don’t have to be a stout lover to enjoy this cake!
Why You’ll Love This Cake
- Made with just two bowls (and a hand mixer)
- Needs only a single 14.9oz can of Guinness Draught Stout
- Has Guinness in both the cake and frosting
- A fun way to incorporate a beloved beverage into a family-friendly dessert

What You’ll Need
- All-purpose flour makes up the bulk of the cake batter. I like to use an unbleached variety, but bleached will work as well.
- Cocoa powder brings the chocolate flavor to this cake. You’ll want to use a regular, natural cocoa powder in this recipe (not Dutched cocoa).
- Baking soda leavens the cake.
- Salt enhances flavor and cuts sweetness.
- Light brown sugar adds sweetness to the cake. I like the added moisture that brown sugar brings to this cake. In a pinch, dark brown sugar will work in this recipe as well.
- Eggs bind the ingredients together and help with the texture and lift of the cake. I haven’t tested this recipe with any egg replacements.
- Olive oil is my go-to baking oil. Feel free to use your favorite baking oil in this recipe, though I don’t recommend coconut oil.
- Plant-based milk adds moisture and is mixed with a small amount of white vinegar to introduce more acid to the cake (which aids in the cake’s leavening/lift).
- White vinegar is mixed with the plant-based milk to aid in the cake’s leavening. Feel free to use apple cider vinegar in its place.
- Vanilla extract adds flavor.
- Guinness acts like coffee in a chocolate cake – it enhances the chocolate flavor. I haven’t tested this recipe with any other stout beers.

More Chocolate Cake Recipes
Chocolate Guinness Baked Donuts
Chocolate Birthday Cake
Chocolate Sheet Cake with Dark Chocolate Frosting
Chocolate Banana Snack Cake

Chocolate Guinness Snack Cake

A simple chocolate sheet cake made with rich cocoa powder and Guinness stout. Topped with a vanilla buttercream frosting, this cake is perfect for enjoying alongside a tasty pint of Irish beer.
Ingredients
Cake
- 1 cup + 2 Tbsp (146g) unbleached all-purpose flour
- 3/4 cup (60g) regular cocoa powder
- 3/4 tsp baking soda
- 3/4 tsp salt
- 3/4 cup (128g) light brown sugar, loosely packed (scooped with measuring cup and leveled)
- 3 large eggs, room temperature
- 1/3 cup olive oil
- 1/3 cup plant-based milk
- 1/2 tsp white vinegar (or apple cider vinegar)
- 1 1/2 tsp vanilla extract
- 1 1/2 cups Guinness Draught Stout Beer (will reduce in Step 1)
Frosting
- 1/2 cup (113g) plant-based butter (or regular butter), softened
- 2 tsp vanilla extract
- 3 cups (360g) powdered sugar
- 1-2 Tbsp reduced Guinness, or milk of choice (see Note 2)
Instructions
Bake the Cake
- Bring your eggs to room temperature by placing them in a glass of very warm water for at least 10 minutes.
- Meanwhile, add the 1 1/2 cups of Guinness to a medium saucepan and bring to a boil. Keep an eye on the beer as it will bubble and foam for the first five minutes or so - you'll need to use a utensil to stir the foam and keep it from overflowing.
- Once the beer boiling, lower the heat to medium and simmer until the beer reduces to roughly 3/4 cup plus 2 Tablespoons (see Note 2). This should take between 10 and 15 minutes. Once reduced, measure out 3/4 cup of the beer and set aside. The remaining 2 Tbsp of reduced beer can be set aside separately.
- Preheat your oven to 325°F and prepare an 8x8" baking pan with non-stick spray and parchment paper. I like to cut one piece of parchment that will cover the bottom and two sides (feel free to line all four sides by using two pieces of paper, if you prefer). Fold the remaining paper over the sides and trim with scissors.
- In a glass measuring cup, add the 1/3 cup of plant-based milk and 1/2 tsp of white vinegar. Give the mixture a quick stir; set aside.
- In a large bowl, sift in the flour and then the cocoa powder. Add the baking soda, salt, and brown sugar and whisk everything together until well combined; set aside.
- In a small bowl, add the eggs, oil, milk/vinegar, and vanilla. Whisk everything together. Slowly pour in 3/4 cup of the reduced Guinness while whisking.
- Add the wet ingredients into the dry and beat with a hand mixer on medium speed for 30 seconds. Pour the batter into your prepared baking pan. Tap the pan on the counter to release air bubbles (I like to do this up to 20 times).
- Bake at 325°F for 35-40 minutes or until a toothpick inserted into the cake comes out with a few crumbs. Allow the cake to cool in the pan for 10 minutes. Run a butter knife along the two edges without parchment paper, and then carefully invert the cake onto a cooling rack. Peel off the parchment paper and toss in the trash.
- Allow the cake to cool completely before making the frosting.
Frost the Cake
- In a large bowl, beat together the softened butter and vanilla extract.
- Add in the powdered sugar and beat (slowly at first) until the ingredients are incorporated - it's okay if it looks like crumbs.
- Add the reduced Guinness (or milk of choice) 1 Tbsp at a time, beating after each addition until the frosting reaches a stiff but spreadable consistency. I like to take my icing spatula and make a swirl in the frosting to see if it's thin/thick enough for my liking. If it looks too thick, add more liquid. If it's too thin, add a bit more powdered sugar.
- Once the frosting is made, use a large spoon or spatula to scoop it all onto the cooled cake. Use a flat icing spatula to spread and swirl the frosting over the surface of the cake.
- Slice and enjoy! Store leftover cake in an airtight container at room temperature.
Notes
- Brown Sugar: for this recipe, you don't want to firmly pack the brown sugar into your measuring cup. I've found that using the cup to scoop the sugar directly from the bag and then leveling off the excess with a knife produces the required weighted amount of brown sugar (i.e. "loosely packed").
- Guinness: if you prefer (or if you accidentally reduced your Guinness too much and don't have enough for the frosting!), you can replace the Guinness in the frosting with your favorite plant-based milk or regular milk.
Did you make this recipe? I would love to see!
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