Guinness Brownies with Frosting
These Guinness brownies are rich, fudgy, and deeply chocolatey with a dark, malty undertone from reduced stout. The brownie interior is dense and moist, with a slightly chewy edge and a glossy top. The frosting is silky and keeps a hint of beer flavor that pairs beautifully with the semi-sweet chocolate base. You will notice warm cocoa and roasted malt aromas as they bake, and a subtle coffee-like note if you include the optional espresso powder. This recipe is ideal for St. Patrick’s Day gatherings, cozy evenings by the fire, or any time you want a grown-up dessert that balances sweet and slightly bitter flavors. They hold up well for parties because the frosting sets firm enough for neat squares, and the brownies stay moist for days when stored properly. Expect compliments and requests for the recipe when you bring these to a potluck.
Ingredients
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11.2–12-ounce bottle Guinness Draught Stout beer, reduced
Reduces down to concentrate flavor and remove some alcohol; yields about 2/3 cup for the batter and a few tablespoons for the frosting. -
3/4 cup unsalted butter (for brownie base)
Adds richness and helps create a fudgy crumb. -
8 ounces semi-sweet chocolate, coarsely chopped
Melts into the butter to form the chocolate backbone of the brownies. -
1 and 1/4 cups granulated sugar
Sweetens the batter and contributes to a shiny brownie top. -
3 large eggs, at room temperature
Provide structure, moisture, and glossy sheen when beaten into the batter. -
1 teaspoon pure vanilla extract
Enhances the chocolate and malt flavors. -
1 cup all-purpose flour
Gives structure without making the brownies cakey. -
1/2 teaspoon salt
Balances sweetness and intensifies chocolate flavor. -
1/2 teaspoon espresso powder (optional)
Boosts chocolate depth and complements the stout; optional but recommended for a richer profile.
Frosting ingredients
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1/2 cup unsalted butter, softened (for frosting)
The base for a creamy, spreadable frosting. -
2 cups confectioners’ sugar
Sweetens and stabilizes the frosting to a smooth consistency. -
2–3 tablespoons reduced Guinness (for frosting)
Adds signature stout flavor; adjust between 2 and 3 tablespoons to reach desired consistency and taste. -
1 teaspoon espresso powder (for frosting)
A small boost of coffee flavor that enhances the chocolate and stout notes. -
1/2 teaspoon pure vanilla extract (for frosting)
Rounds and lifts the frosting flavor. -
1/4 teaspoon salt (for frosting)
Balances sweetness and brightens the overall taste.
Step-by-step Instructions
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Reduce the Guinness. Pour the 11.2 to 12-ounce bottle into a small saucepan and simmer over medium-high heat until reduced to about 2/3 cup. This concentrates the flavor and evaporates some alcohol. Remove from heat and let cool while you prepare other ingredients.
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Preheat and prepare the pan. Preheat your oven to 350°F (175°C). Grease a 9-inch square baking pan with butter or nonstick spray, or line it with parchment for easier removal.
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Melt butter and chocolate. Place 3/4 cup unsalted butter and 8 ounces coarsely chopped semi-sweet chocolate in a microwave-safe bowl. Microwave in 20 to 30 second bursts, stirring between bursts, until completely smooth to avoid overheating the chocolate.
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Combine sugar and reduced Guinness. Whisk 1 and 1/4 cups granulated sugar into the melted chocolate mixture, then whisk in the cooled reduced Guinness until evenly incorporated.
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Add eggs and vanilla. Add the 3 large room-temperature eggs one at a time or all together, whisking until the mixture is glossy. Stir in 1 teaspoon pure vanilla extract.
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Fold in dry ingredients. Gently mix in 1 cup all-purpose flour, 1/2 teaspoon salt, and 1/2 teaspoon espresso powder if using, until just combined. Avoid overmixing to keep the brownies fudgy.
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Bake the brownies. Pour the batter into the prepared 9-inch square pan and smooth the top. Bake in the preheated oven for 32 minutes. Check doneness by inserting a toothpick into the center; it should come out with a few moist crumbs but not wet batter.
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Cool completely. Remove the pan from the oven and let the brownies cool completely in the pan. Cooling fully is important so the frosting does not melt.
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Make the frosting. In a mixing bowl, beat 1/2 cup softened unsalted butter until creamy. Gradually add 2 cups confectioners’ sugar while mixing on low. Add 2 to 3 tablespoons of the reduced Guinness, 1 teaspoon espresso powder, 1/2 teaspoon pure vanilla extract, and 1/4 teaspoon salt, and beat until smooth and spreadable. If the frosting is too thin, add a little more confectioners’ sugar; if too thick, add an extra teaspoon of reduced Guinness.
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Frost, set, and store. Spread the frosting evenly over the cooled brownies. Let the frosting set at room temperature, then cut into squares. Store the brownies at room temperature in an airtight container.
Recipe Details
- Prep Time: 25 minutes (includes reducing Guinness and prep)
- Cook Time: 32 minutes (baking)
- Total Time: 2 hours 27 minutes (includes cooling and frosting set time)
- Servings: about 16 squares
- Calories: approximately 370 kcal per serving
Tips, Storage & Variations
Tips
- When melting chocolate, short microwave bursts and stirring prevent scorching.
- Use room-temperature eggs to help the batter emulsify and become glossy.
- To test doneness, look for a shiny top and moist crumbs on a toothpick rather than a completely clean toothpick.
Storage
- Store frosted brownies at room temperature in an airtight container for up to 3 days.
- If your kitchen is warm, store in the refrigerator and bring to room temperature before serving for the best texture.
Freezing
- Freeze unfrosted brownies tightly wrapped for up to 3 months. Thaw overnight in the refrigerator and frost before serving.
- You can also freeze frosted brownies in a single layer, well wrapped, for up to 1 month. Thaw in the refrigerator to preserve frosting texture.
Flavor variations using existing ingredients only
- Mocha boost: Add the optional 1/2 teaspoon espresso powder to both the batter and the frosting for a stronger coffee-chocolate note.
- Extra chocolate pockets: Fold a handful of the chopped semi-sweet chocolate into the batter before baking for melty chocolate pockets.
- Stronger stout flavor: Use 3 tablespoons of reduced Guinness in the frosting and 2/3 cup in the batter to emphasize the beer note.
Frequently Asked Questions
Q: Can I use regular beer instead of Guinness?
A: Guinness has a distinct roasted malt flavor that complements chocolate. A different stout may work, but avoid light lagers for best results.
Q: Do I need to reduce the Guinness?
A: Yes. Reducing concentrates the flavor and helps remove some alcohol so the stout flavor remains without thinning the batter.
Q: Can I make these ahead of time?
A: Yes. Bake and frost the brownies a day ahead. Store at room temperature in an airtight container.
Q: How do I prevent the frosting from being too runny?
A: Gradually add confectioners’ sugar to reach a spreadable but firm consistency, or use the lower end of the reduced Guinness amount.
Q: Can I skip the espresso powder?
A: Yes. It is optional but enhances chocolate depth. The brownies are delicious without it.
Q: How should I cut neat squares?
A: Chill the frosted brownies briefly, then use a sharp knife wiped clean between cuts for tidy edges.
People Also Ask
Q: What does Guinness do in brownies?
A: It adds roasted, malty complexity and balances sweetness with a subtle bitterness that enhances chocolate flavor.
Q: How long does it take to reduce Guinness to 2/3 cup?
A: Typically 8 to 12 minutes over medium-high heat, depending on your pan and heat intensity.
Q: Can I make these in a different pan size?
A: You can, but baking time will change. A larger pan will bake faster and a smaller pan will need more time.
Q: Will the brownies taste boozy?
A: Reducing the beer concentrates flavor while evaporating much of the alcohol, so the brownies taste malty rather than boozy.
Q: Is confectioners’ sugar different from granulated sugar in frosting?
A: Yes. Confectioners’ sugar has cornstarch and is finer, which makes frosting smooth and stable.
Q: Can I omit the frosting?
A: Yes. The brownies are rich enough on their own, but the frosting adds a creamy contrast and a layered stout flavor.
Q: How do I warm up chilled brownies before serving?
A: Bring to room temperature or microwave individual squares for 8 to 10 seconds to soften slightly.
Q: Does espresso powder make the brownies taste like coffee?
A: Espresso powder enhances and deepens chocolate flavor without making the brownies taste strongly of coffee when used in small amounts.
Conclusion
These Guinness Brownies with Frosting make a showstopping dessert that balances deep chocolate with malty stout notes. They are perfect for special occasions or whenever you want a decadent, grown-up treat. For additional inspiration and variations from other bakers, you might enjoy the classic take at Guinness Brownies – Sally’s Baking Addiction and a different frosting idea at Guinness Chocolate Brownies Baileys Frosting. Give this recipe a try, share a pan with friends, and enjoy the warm compliments that follow.
Guinness Brownies with Frosting
Ingredients
Method
- Reduce the Guinness. Pour the 11.2 to 12-ounce bottle into a small saucepan and simmer over medium-high heat until reduced to about 2/3 cup. This concentrates the flavor and evaporates some alcohol. Remove from heat and let cool while you prepare other ingredients.
- Preheat and prepare the pan. Preheat your oven to 350°F (175°C). Grease a 9-inch square baking pan with butter or nonstick spray, or line it with parchment for easier removal.
- Melt butter and chocolate. Place 3/4 cup unsalted butter and 8 ounces coarsely chopped semi-sweet chocolate in a microwave-safe bowl. Microwave in 20 to 30 second bursts, stirring between bursts, until completely smooth to avoid overheating the chocolate.
- Combine sugar and reduced Guinness. Whisk 1 and 1/4 cups granulated sugar into the melted chocolate mixture, then whisk in the cooled reduced Guinness until evenly incorporated.
- Add eggs and vanilla. Add the 3 large room-temperature eggs one at a time or all together, whisking until the mixture is glossy. Stir in 1 teaspoon pure vanilla extract.
- Fold in dry ingredients. Gently mix in 1 cup all-purpose flour, 1/2 teaspoon salt, and 1/2 teaspoon espresso powder if using, until just combined. Avoid overmixing to keep the brownies fudgy.
- Bake the brownies. Pour the batter into the prepared 9-inch square pan and smooth the top. Bake in the preheated oven for 32 minutes. Check doneness by inserting a toothpick into the center; it should come out with a few moist crumbs but not wet batter.
- Cool completely. Remove the pan from the oven and let the brownies cool completely in the pan. Cooling fully is important so the frosting does not melt.
- Make the frosting. In a mixing bowl, beat 1/2 cup softened unsalted butter until creamy. Gradually add 2 cups confectioners’ sugar while mixing on low. Add 2 to 3 tablespoons of the reduced Guinness, 1 teaspoon espresso powder, 1/2 teaspoon pure vanilla extract, and 1/4 teaspoon salt, and beat until smooth and spreadable.
- Frost, set, and store. Spread the frosting evenly over the cooled brownies. Let the frosting set at room temperature, then cut into squares. Store the brownies at room temperature in an airtight container.