The Gay Globetrotter

Dark Chocolate Guinness Brownies

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Guinness brownies are oh-so decadent, and filled with dark chocolate, stout, and espresso flavor. They’re topped with a rich espresso Guinness buttercream for the perfect, cakey brownies!

Brownies always go fast around here, and these ones are just perfect for St Patrick’s Day. Serve them after a cabbage and sausage skillet dinner with some Irish coffee and shamrock shakes for the perfect Irish spread.

Guinness brownies with icing stacked next to a can of beer.

Cakey vs Fudgy – What’s Your Preference?

Cakey vs fudgy brownies. Cakey brownies have a higher flour vs fat (chocolate and butter) ratio, so they are lighter, and more cake like. Cakey brownies also may contain leavening agents like baking powder.

Fudgy brownies have a higher butter and chocolate content, and become more dense, almost like a fudge.

If you prefer cakey brownies, use the whole cup of flour in this recipe. For a more fudgy brownie, use ¾ cup of flour in the recipe.

Dark chocolate being chopped on a cutting board.

How To Make Guinness Brownies

To make these Guinness brownies:

  1. Begin by preheating the oven to 350°F. Grease 9×9″ baking dish with butter, then flour it, shaking out excess.
  2. Make the Guinness reduction by pouring the stout into a saucepan over high heat. Reduce until about 2/3 cup remains. Pour the Guinness reduction into a liquid measure to cool for about 15 minutes while you prep the rest.
  3. Chop the dark chocolate, and add it to a microwave safe bowl. Add butter. Microwave at 30 second intervals, mixing in between until the mixture is smooth. Add in sugar, 1/2 cup of Guinness reduction, vanilla, eggs until the mixture is smooth.
  4. Add flour and salt. mixing until mixture is just combined. It should be nice and thick. Pour into prepared baking dish.
  5. Bake for 30-35 minutes or until a toothpick comes out with loose crumbs, not clean. If the toothpick comes out with batter, continue to bake at 3 minute increments until you see wet crumbs. Cool brownies on a wire rack completely before frosting.

Brownie batter being poured into a baking dish.

How To Make Guinness Buttercream

To make the Guinness espresso buttercream:

  1. Using a stand mixer or hand mixer, beat the room temperature butter on high speed until creamy. The creamier you can get it, the better. No lumps should remain.
  2. Add the icing sugar, and mix slowly, increasing speed as it incorporates. Add vanilla, espresso powder, and begin adding Guinness reduction, a tablespoon at a time, until mixture is a light and fluffy consistency.

Guinness being poured into a saucepan.

Guinness Brownies Tips and Substitutions

  • You can omit the espresso powder in the recipe, if desired.
  • Alcohol is cooked out of the Guinness during the cooking process.
  • Brownies can over bake quickly, so check them every 3 minutes to make sure they aren’t overdone. If a toothpick comes out clean, they’re overcooked.
  • Allow brownies to cool completely before icing or cutting. If not, the buttercream will melt while icing them.
  • The buttercream will begin being very dense, and lighten as the Guinness reduction is added to it.

Brownie batter in a baking dish.

Storing Guinness Brownies

Guinness brownies can be stored in the fridge for up to 5 days.

Place them in an air tight container rather than using plastic wrap to preserve the icing.

If you’d like to freeze Guinness brownies, avoid icing them. Once cooled, wrap with plastic wrap and place in the freezer for up to 3 months. Defrost on the counter at room temperature before icing and serving.

More Decadent Dessert Recipes

Guinness brownies with icing stacked next to a can of beer.
Rate this Recipe
4 from 3 votes

Dark Chocolate Guinness Brownies With Buttercream

Prep Time: 25 mins
Cook Time: 35 mins
Cooling Time: 2 hrs
Total Time: 3 hrs
Servings: 12 brownies
Author: Bailey
These Guinness brownies are topped with a quick homemade buttercream and filled with dark chocolate, and stout beer flavor.
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Tried this recipe?I'd love to hear what you think. Leave a comment and rating below!


  • ½ cup butter unsalted
  • 6 ounces dark chocolate bakers chocolate, 2 bars
  • 1 ½ cups granulated sugar
  • 12 ounces Guinness beer 1 bottle, or can
  • 1 teaspoon vanilla
  • 3 eggs
  • ½ teaspoon espresso powder
  • 1 cup flour


  • ½ cup butter softened
  • 2 cups powdered sugar
  • ½ teaspoon espresso powder


  • Preheat oven to 350°F. Grease and flour a 9x9" baking dish.
  • Pour Guinness into a saucepan over high heat. Reduce until 2/3 cup remains, 10-12 minutes. Pour Guinness reduction into a heat safe liquid measuring cup to cool for at least 15 minutes.
  • Meanwhile, add dark chocolate and butter to a medium microwave safe bowl. Melt in 30 second increments, stirring between each one until mixture is smooth. Stir in sugar, eggs, vanilla, and ½ cup of the Guinness reduction. Add salt and flour, mixing until just combined without overmixing. Batter will be thick.
  • Pour batter into prepared baking dish. Bake for 30-35 minutes, or until a toothpick comes out with wet crumbs (not batter). If toothpick has batter, return to the oven and cook with 3 minute increments until wet crumbs are achieved. Cool brownies on a wire rack for at least 2 hours until fully cooled.
  • Meanwhile, for the buttercream, beat softened butter until fully creamed and no lumps remain using a stand mixer or hand mixer. Add powdered sugar and espresso powder, and mix until smooth (it will be thick and dense). Add remaining Guinness reduction, a tablespoon at a time, until buttercream becomes light and fluffy.
  • Frost brownies with prepared buttercream, then cut into squares.


You can omit the espresso powder in the batter and buttercream, if desired.
For fudgier brownies, reduce the amount of flour added to ¾ cup.
Calories: 545kcal | Carbohydrates: 67g | Protein: 5g | Fat: 29g | Saturated Fat: 17g | Trans Fat: 1g | Cholesterol: 82mg | Sodium: 157mg | Potassium: 238mg | Fiber: 3g | Sugar: 51g | Vitamin A: 543IU | Calcium: 34mg | Iron: 4mg

This recipe was inspired by Guinness Brownies from Sally’s Baking Addiction.

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Brownies stacked next to a can of Guinness with text overlay.

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