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guinness brownie with baileys frosting on a white surface with a bite missing

Guinness Chocolate Brownies Baileys Frosting

Rich, Chocolate Brownies made with Guinness Stout are topped with a Bailey's infused Cream Cheese Frosting. The perfect Irish treat to celebrate St. Patrick's Day or a lovely boozy treat for your next party!

  • Total Time: 1 hour
  • Yield: 9-16 Pieces 1x


  • 3oz (1/4 Cup + 2 Tablespoons) Guinness (reduced from 6oz 3/4 Cup)
  • 1oz (2 Tbsp) Unsalted Butter
  • 250 Grams(1 1/4 cups) Granulated Sugar
  • 90 Grams (3/4 cups) Dutch-process Cocao Powder, my favorite is Bensdorp Dutch Cocoa Powder (affiliate link)
  • 3.5oz (scant 1/2 cup) Vegetable Oil
  • 2 Teaspoons Pure Vanilla Extract
  • 1 Large Egg Yolk and 1 Large Egg, at room temp.
  • 1/8 Teaspoon Baking Soda
  • 1/2 Teaspoon Salt
  • 1 Tablespoon Cornstarch/ Cornflour
  • 75 Grams (scant 2/3 cup) All-Purpose Flour/ Plain Flour
  • 2oz (1/4 cup) Chocolate (chips, chunks, or bars chopped)
  • 1/2 Recipe of Baileys Swiss Meringue Buttercream


  1. In a large pot add the Guinness and let it cook over medium heat for 5-10 minutes, you want the mixture to reduce by 50% so you are left with a concentrated 3oz of Guinness flavor. Preheat the oven to 350F/180C and line a 9-inch square pan with foil so that it overhangs on the sides then grease the foil heavily with non-stick baking spray.
  2. Once the Guinness has reduced add the butter and sugar. Let it all cook on low heat until the butter has melted the sugar is completely incorporated. Cooking the sugar helps create that chewy brownie with a crinkly top. Let the mixture cool for 5 minutes then transfer to a bowl.
  3. Add the cocoa powder and vegetable oil to the cooled Guinness mixture, making sure to mix until fully combined.
  4. Next, add the vanilla, egg, and egg yolk. Whisk to combine. Add the baking soda, salt, cornstarch and mix to combine. Gently add the flour by using a spatula to fold in until just combined, just before there are no flour streaks add your chocolate chunks/ chips. Do not over mix, this will affect the end product.
  5. Pour into prepared pan and bake 25-27 minutes, or until when you stick a toothpick in no liquid batter comes out just moist crumbs. Let cool completely before frosting
  6. Use an offset spatula to create nice swirls of the frosting cut into pieces, I like 16 pieces as they are quite sweet. Store the brownies at room temperature unless in a warm environment store in the fridge. 
  • Author: Elizabeth I Confessions of a Baking Queen
  • Prep Time: 25 minutes
  • Cook Time: 35 minutes
  • Category: Dessert
  • Method: Bake
  • Cuisine: American

Keywords: guinness brownies, guinness recipe, boozy brownies

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