Guinness Brownies with Frosting

Warm, fudgy, and a little bit boozy, these Guinness Brownies with Frosting balance deep chocolate richness with a subtle roasted stout note. The brownies have a glossy, slightly crackled top, a dense and gooey center, and a moist crumb that comes from the reduced Guinness and melted chocolate. The frosting is silky and lightly sweet, with a hint of espresso and beer to tie it to the base. You will notice dark cocoa aromas with roasted malty undertones as they bake. These brownies are ideal for weekend baking, potlucks, St. Patrick’s Day gatherings, or anytime you want a grownup twist on a classic treat. If you enjoy pairing desserts with savory mains, try these after a comforting casserole for a satisfying meal finish, such as this crockpot pierogi casserole with kielbasa recipe crockpot pierogi casserole with kielbasa.

Ingredients

11.2 to 12-ounce bottle Guinness Draught Stout beer, reduced to concentrate: the stout is simmered down to concentrate flavor; measure after reducing.
3/4 cup unsalted butter: melts into the batter to create richness and a fudgy texture.
8 ounces semi-sweet chocolate, coarsely chopped: provides the deep chocolate base; good-quality chocolate makes a difference.
1 and 1/4 cups granulated sugar: sweetens and helps create that shiny brownie top.
3 large eggs, at room temperature: add structure and moisture; room temperature eggs incorporate more evenly.
1 teaspoon pure vanilla extract: enhances chocolate flavor.
1 cup all-purpose flour: the only flour used; measure gently for tender brownies.
1/2 teaspoon salt: balances sweetness and sharpens flavor.
1/2 teaspoon espresso powder (optional): brightens the chocolate if using.
1/2 cup unsalted butter, softened for frosting: makes the frosting creamy and spreadable.
2 cups confectioners’ sugar: sweetens and gives the frosting a smooth texture.
2 to 3 tablespoons reduced Guinness for frosting: adds beer flavor and thins the frosting to the right consistency.
1 teaspoon espresso powder for frosting: adds depth and enhances chocolate notes.
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. In a small saucepan, bring the Guinness to a boil over medium-high heat. Reduce to medium heat and simmer until reduced down to 2/3 cup, about 12 to 15 minutes. Cool for at least 10 minutes. Tip: watch closely near the end so it does not burn.
Prepare the oven and pan. Preheat the oven to 350°F (175°C) and grease a 9-inch square baking pan. Line with parchment if desired for easy removal.
Melt chocolate and butter. In a microwave-safe bowl, melt 3/4 cup unsalted butter and 8 ounces coarsely chopped semi-sweet chocolate in 30-second increments, whisking between bursts until smooth.
Combine sugar and Guinness. Whisk in 1 and 1/4 cups granulated sugar and 1/2 cup of reduced Guinness until combined. Then whisk in 3 large eggs and 1 teaspoon vanilla until the mixture is glossy.
Add dry ingredients. Add 1 cup all-purpose flour, 1/2 teaspoon salt, and 1/2 teaspoon espresso powder if using. Whisk until thick and shiny; do not overmix.
Bake the brownies. Pour the batter into the prepared pan and bake for 32 minutes. A toothpick inserted should come out with a few moist crumbs.
Cool completely. Allow brownies to cool in the pan before frosting to prevent the frosting from melting.
Make the frosting. Beat 1/2 cup softened unsalted butter until smooth, then gradually mix in 2 cups confectioners’ sugar. Add 2 to 3 tablespoons reduced Guinness, 1 teaspoon espresso powder, 1/2 teaspoon vanilla extract, and 1/4 teaspoon salt until smooth. Adjust Guinness amount to reach your preferred spreadable consistency.
Frost and cut. Frost the cooled brownies, then cut into squares once set. Tip: chill briefly to make clean slices.
Store. Keep covered at room temperature for up to 1 week.

Recipe Details

Prep Time: 25 minutes active, plus 12 to 15 minutes to reduce Guinness and 10 minutes cooling.
Cook Time: 32 minutes.
Total Time: About 1 hour including cooling and reduction.
Servings: 16 squares.
Calories: About 360 calories per serving. For another filling comfort dish to serve alongside or before dessert, consider this pierogi casserole with kielbasa.

Tips, Storage & Variations

Practical tips: Use room temperature eggs for a silkier batter. Whisk the chocolate mixture until fully smooth to avoid grainy texture. If you prefer thicker frosting, use 2 tablespoons of reduced Guinness; for thinner frosting use 3 tablespoons.
Storage: Store the frosted brownies in an airtight container at room temperature for up to 1 week.
Freezing: Wrap cooled, unfrosted brownies tightly and freeze up to 3 months. Thaw before frosting. You can also freeze frosted squares between sheets of parchment for up to 2 months.
Flavor variations using existing ingredients only: Add the optional 1/2 teaspoon espresso powder in the batter for a more intense chocolate note, or increase the frosting espresso powder slightly for a coffee-kissed finish. For a richer frosting texture, chill the butter slightly before beating. For a softer bite, reduce baking time by 1 to 2 minutes.
For ideas on pairing with savory mains or slow cooker techniques, check this slow cooker garlic butter beef recipe slow cooker garlic butter beef with potatoes and these tips from a creamy mac and cheese pairing honey pepper chicken with creamy mac and cheese.

FAQ

Can I use regular beer instead of Guinness?
Yes, but Guinness gives a distinct roasted malt flavor. A similarly dark stout is the best substitute.
Do I have to reduce the Guinness?
Yes, reducing concentrates the flavor and removes excess water so the batter keeps the right texture.
Can I make these ahead of time?
Yes, bake and frost ahead. Store at room temperature up to 1 week or freeze unfrosted for longer storage.
How do I know when brownies are done?
A toothpick should come out with a few moist crumbs; the center should look set but fudgy.
Is espresso powder necessary?
No, it is optional. It brightens the chocolate but the brownies will still be great without it.
Can I use salted butter instead of unsalted?
Yes, but reduce the added salt by a pinch in both batter and frosting.

Conclusion

These Guinness Brownies with Frosting bring together fudgy chocolate, stout complexity, and a creamy espresso-kissed glaze for a memorable dessert. If you enjoyed this recipe, you might like a classic take by Sally that inspired many bakers or a different frosting approach for Guinness brownies at another blog. For more baking inspiration, see this version from Sally at Guinness Brownies – Sally’s Baking Addiction and explore a creative frosting idea at Guinness Chocolate Brownies Baileys Frosting. Try the recipe, share a batch with friends, and enjoy the cozy flavors.

Guinness Brownies with Frosting

Print Recipe

Warm, fudgy brownies with a subtle roasted stout flavor and a creamy espresso-kissed frosting.

Author: amanda-lewis
Prep Time: 25 minutes
Cook Time: 32 minutes
Total Time: 60 minutes
Yield: 16 squares 1x
Category: Dessert
Method: Baking
Cuisine: American
Diet: Vegetarian

Ingredients

Scale

1 bottle (11.2 to 12 ounces) Guinness Draught Stout beer, reduced to concentrate
3/4 cup unsalted butter
8 ounces 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, softened for frosting
2 cups confectioners’ sugar
2 to 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 by boiling it in a saucepan until it reduces to 2/3 cup, about 12 to 15 minutes. Cool for about 10 minutes.
Prepare the oven and pan by preheating to 350°F (175°C) and greasing a 9-inch square baking pan.
Melt the butter and chocolate in a microwave-safe bowl in 30-second increments, whisking until smooth.
Combine the granulated sugar and reduced Guinness, then whisk in eggs and vanilla until glossy.
Add flour, salt, and espresso powder, whisking until just combined.
Bake for 32 minutes or until a toothpick comes out with a few moist crumbs.
Cool the brownies completely before frosting.
Make the frosting by beating softened butter until smooth, then gradually mix in confectioners’ sugar, reduced Guinness, espresso powder, vanilla, and salt until smooth.
Frost the cooled brownies and cut into squares.