Guinness Brownies with Guinness Frosting

Introduction
These Guinness Brownies with Guinness Frosting are rich, fudgy, and satisfyingly boozy without being overpowering. The stout reduces into a deep, malty syrup that amplifies the chocolate and adds a subtle roasted flavor, while the dense brownie crumb stays moist and chewy. The frosting is silky and lightly boozy, with a whisper of espresso that sharpens the chocolate notes. These brownies are perfect for St. Patrick’s Day gatherings, cozy evenings by the fire, or any time you want an elevated chocolate treat to share. If you pair desserts with hearty mains, you might enjoy a contrasting savory casserole like this crockpot pierogi casserole with kielbasa after serving these brownies.

Ingredients

1 (11.2–12-ounce) bottle Guinness Draught Stout beer, reduced, to concentrate flavor and remove most of the alcohol.
3/4 cup unsalted butter, for the brownie batter, provides richness and fudgy texture.
2 (4-ounce) bars semi-sweet chocolate, coarsely chopped, for deep chocolate flavor and a glossy crumb.
1 and 1/4 cups granulated sugar, sweetens and helps create a tender, slightly crackly top.
3 large eggs, at room temperature, for structure and moisture.
1 teaspoon pure vanilla extract, to round and enhance the chocolate notes.
1 cup all-purpose flour, for structure without making the brownies cakey.
1/2 teaspoon salt, balances sweetness and tightens flavor.
1/2 teaspoon espresso powder (optional), intensifies chocolate flavor without adding coffee taste.
1/2 cup unsalted butter (for frosting), for a creamy, spreadable frosting base.
2 cups confectioners’ sugar, sweetens and thickens the frosting smoothly.
2–3 tablespoons reduced Guinness (for frosting), adds malty, boozy flavor and thins frosting to the right consistency.
1 teaspoon espresso powder (for frosting), a small boost to lift the chocolate in the frosting.
1/2 teaspoon pure vanilla extract (for frosting), rounds the frosting flavors.
1/4 teaspoon salt (for frosting), balances the sweetness in the frosting.

Step-by-Step Instructions

Reduce the Guinness. Pour the bottle of Guinness into a small saucepan and bring to a boil over medium-high heat. Once boiling, lower the heat and simmer until reduced to 2/3 cup, about 12 to 15 minutes. Tip: watch carefully as the foam can rise quickly.
Cool the reduced Guinness. Remove the pan from heat and let the reduced Guinness cool to room temperature before using it in the batter.
Preheat and prepare the pan. Preheat your oven to 350°F (175°C). Grease a 9-inch square baking pan so the brownies release cleanly after baking.
Melt butter and chocolate. In a microwave-safe bowl, combine 3/4 cup unsalted butter and the coarsely chopped chocolate. Microwave at 30-second intervals, stirring between each, until fully melted and smooth.
Combine sugar and Guinness. Stir the granulated sugar and 1/2 cup of the reduced Guinness into the melted chocolate mixture until evenly mixed and slightly glossy.
Add eggs and vanilla. Add the 3 large eggs, one at a time if you prefer, and whisk in the 1 teaspoon pure vanilla extract until the batter is smooth and homogeneous.
Mix in dry ingredients. Gently fold in the 1 cup all-purpose flour, 1/2 teaspoon salt, and 1/2 teaspoon espresso powder if using, until no streaks of flour remain. Avoid overmixing to keep the brownies tender.
Bake the brownies. Pour the batter into the prepared 9-inch square pan and smooth the top. Bake for 32 to 35 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs. Tip: a slightly underbaked center yields the fudgiest result.
Cool completely. Remove the brownies from the oven and allow them to cool completely in the pan on a wire rack before frosting.
Make the frosting. In a mixing bowl, beat the softened 1/2 cup unsalted butter until creamy. Gradually add the 2 cups confectioners’ sugar, beating until incorporated and smooth.
Finish and frost. Add 2 to 3 tablespoons of the reduced Guinness, 1 teaspoon espresso powder, 1/2 teaspoon vanilla extract, and 1/4 teaspoon salt to the frosting. Mix until you reach a spreadable consistency. Spread the frosting over the cooled brownies, then cut into squares once set.

Recipe Details

Prep Time: 25 minutes, plus 12 to 15 minutes to reduce Guinness and cooling time.
Cook Time: 32 to 35 minutes baking time.
Total Time: About 1 hour 15 minutes including reduction and cooling.
Servings: Makes about 12 generous brownies.
Calories: Approximately 490 calories per serving.

(For a savory follow-up to this treat, consider serving after a main like this kielbasa pierogi casserole.)

Tips, Storage & Variations

Small tips: Let the reduced Guinness cool before adding to eggs to prevent cooking the eggs. Stir the chocolate mixture between microwave intervals for a smooth finish.
Storage: Store frosted brownies in an airtight container at room temperature for up to 3 days. Refrigerate if your kitchen is warm, and bring to room temperature before serving.
Freezing: Wrap individual unfrosted brownies tightly and freeze for up to 2 months. Thaw overnight in the refrigerator and frost once softened. Frosted brownies can be frozen in a single layer, well wrapped, for up to 1 month.
Flavor variations using existing ingredients only: Add the optional 1/2 teaspoon espresso powder to both batter and frosting for a stronger mocha edge. Use 3 tablespoons of reduced Guinness in the frosting for more pronounced stout flavor, or reduce to 2 tablespoons for a subtler note. For a slightly denser texture, chill the batter for 15 minutes before baking.

(For a cozy main to pair with dessert, you might try a creamy mac and cheese with a sweet and spicy twist like this honey pepper chicken with creamy mac and cheese.)

FAQ

Can I use regular beer instead of Guinness?
No. Guinness has a distinct malty and roasted profile that complements chocolate. Regular lighter beers will not provide the same flavor.
Do these brownies contain a lot of alcohol?
Most alcohol cooks off during the reduction and baking, leaving flavor but little alcohol. The reduced Guinness concentrates flavor while minimizing alcohol content.
Can I make the reduced Guinness ahead of time?
Yes. You can reduce the Guinness and store it in the refrigerator for up to 3 days before using.
How can I tell when the brownies are done?
Insert a toothpick into the center. You want a few moist crumbs attached, not a wet batter. This gives a fudgy texture.
Can I skip the espresso powder?
Yes. Espresso powder is optional and only used to enhance the chocolate. Skipping it will not harm the recipe.

Conclusion

These Guinness Brownies with Guinness Frosting are a celebratory riff on classic brownies, with comforting fudginess and a nuanced stout infusion that makes each bite memorable. If you try this recipe, share your photos and feedback so others can enjoy the results. For more inspiration and a similar take, see this Guinness Brownies with Guinness Frosting – WellPlated.com and this classic version at Guinness Brownies – Sally’s Baking Addiction.

Guinness Brownies with Guinness Frosting

Print Recipe

Rich, fudgy brownies enhanced with a deep, malty flavor from Guinness and topped with a silky frosting that includes a whisper of espresso.

Author: amanda-lewis
Prep Time: 25 minutes
Cook Time: 35 minutes
Total Time: 75 minutes
Yield: 12 servings 1x
Category: Dessert
Method: Baking
Cuisine: Irish
Diet: Vegetarian

Ingredients

Scale

1 (11.2–12-ounce) bottle Guinness Draught Stout beer, reduced
3/4 cup unsalted butter, for the brownie batter
2 (4-ounce) bars semi-sweet chocolate, coarsely chopped
1 and 1/4 cups granulated sugar
3 large eggs, at room temperature
1 teaspoon pure vanilla extract
1 cup all-purpose flour
1/2 teaspoon salt
1/2 teaspoon espresso powder (optional)
1/2 cup unsalted butter (for frosting)
2 cups confectioners’ sugar
2–3 tablespoons reduced Guinness (for frosting)
1 teaspoon espresso powder (for frosting)
1/2 teaspoon pure vanilla extract (for frosting)
1/4 teaspoon salt (for frosting)

Instructions

Reduce the Guinness. Pour the bottle of Guinness into a small saucepan and bring to a boil over medium-high heat. Once boiling, lower the heat and simmer until reduced to 2/3 cup, about 12 to 15 minutes.
Cool the reduced Guinness. Remove the pan from heat and let the reduced Guinness cool to room temperature before using it in the batter.
Preheat and prepare the pan. Preheat your oven to 350°F (175°C). Grease a 9-inch square baking pan.
Melt butter and chocolate. In a microwave-safe bowl, combine 3/4 cup unsalted butter and the coarsely chopped chocolate. Microwave at 30-second intervals, stirring until fully melted and smooth.
Combine sugar and Guinness. Stir the granulated sugar and 1/2 cup of the reduced Guinness into the melted chocolate mixture until evenly mixed.
Add eggs and vanilla. Add the 3 large eggs and whisk in the 1 teaspoon pure vanilla extract until the batter is smooth.
Mix in dry ingredients. Gently fold in the 1 cup all-purpose flour, 1/2 teaspoon salt, and 1/2 teaspoon espresso powder until no streaks of flour remain.
Bake the brownies. Pour the batter into the prepared pan and bake for 32 to 35 minutes.
Cool completely. Remove the brownies from the oven and allow them to cool completely in the pan on a wire rack.
Make the frosting. In a mixing bowl, beat the softened 1/2 cup unsalted butter until creamy. Gradually add the 2 cups confectioners’ sugar, beating until smooth.
Finish and frost. Add 2 to 3 tablespoons of the reduced Guinness, 1 teaspoon espresso powder, 1/2 teaspoon vanilla extract, and 1/4 teaspoon salt to the frosting. Mix until spreadable and spread over the cooled brownies.

Notes

Store frosted brownies in an airtight container at room temperature for up to 3 days. Refrigerate if the kitchen is warm and bring to room temperature before serving.