Guinness Brownies with Guinness Frosting

Name: Guinness Brownies with Guinness Frosting
Prep time: 20 min
Cook time: 35 min
Total time: 55 min
Cuisine: Irish
Ingredients: 1 (11.2–12-ounce) bottle Guinness Draught Stout; 3/4 cup unsalted butter; 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, softened (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)

These Guinness Brownies with Guinness Frosting are rich, fudgy, and deeply chocolatey, with a subtle roasted malt warmth from the stout. The brownies bake up with a glossy, crackly top and a dense, moist interior that almost melts on the tongue. The frosting is silky and balanced, carrying a hint of beer bitterness and espresso that brightens the chocolate. Aromas of dark chocolate and roasted barley fill the kitchen as they bake, making them ideal for a cozy evening dessert, a St. Patrick’s Day celebration, or any time you want an indulgent, grown-up treat. If you enjoy trying different dessert textures, you might also like a nutty twist in our Pecan Pie Cupcakes with Brown Sugar Frosting, and for a savory contrast to serve alongside, see the well-spiced Chicken Shawarma with Garlic Sauce for an informal dinner party.

Ingredients

1 (11.2–12-ounce) bottle Guinness Draught Stout beer, for deep malt flavor and moisture.
3/4 cup unsalted butter, adds richness and tender crumb.
2 (4-ounce) bars semi-sweet chocolate, coarsely chopped, for the chocolate base.
1 and 1/4 cups granulated sugar, to sweeten and help form the crackly top.
3 large eggs, at room temperature, for structure and richness.
1 teaspoon pure vanilla extract, enhances chocolate flavor.
1 cup all-purpose flour, the primary dry structure.
1/2 teaspoon salt, balances sweetness and enhances flavor.
1/2 teaspoon espresso powder (optional), intensifies chocolate notes.

Guinness Frosting:

1/2 cup unsalted butter, softened to room temperature, for a creamy base.
2 cups confectioners’ sugar, smooth sweetness and structure.
2–3 tablespoons reduced Guinness, to echo the brownie flavor in the frosting.
1 teaspoon espresso powder, enhances depth and chocolate brightness.
1/2 teaspoon pure vanilla extract, rounds the flavor.
1/4 teaspoon salt, balances the sweetness.

If you like indulgent, holiday-style cakes, try a boozy twist on a classic in the Cozy Up with Eggnog Poke Cake for another seasonal option.

Step-by-Step Instructions

Reduce the Guinness. In a small saucepan, bring the Guinness to a boil over medium-high heat, then reduce the heat and let it simmer until reduced to 2/3 cup, about 12 to 15 minutes. Let cool. Tip: watch closely near the end to prevent scorching.
Preheat and prepare the pan. Preheat the oven to 350°F (175°C) and grease a 9-inch square baking pan. Lining the pan with parchment makes removal easier.
Melt butter and chocolate. Melt the 3/4 cup unsalted butter and the coarsely chopped semi-sweet chocolate together in a microwave-safe bowl in short bursts, stirring between intervals, until smooth. Alternatively, use a double boiler.
Mix in sugar and Guinness. Whisk the melted butter and chocolate mixture with the 1 and 1/4 cups granulated sugar and 1/2 cup of the reduced Guinness until combined.
Add eggs and vanilla. Add the 3 large eggs, one at a time if you prefer, and the 1 teaspoon pure vanilla extract, then whisk until the mixture is smooth.
Combine dry ingredients. Gently mix in the 1 cup all-purpose flour, 1/2 teaspoon salt, and 1/2 teaspoon espresso powder if using, until just combined. Do not overmix.
Bake. Pour the batter into the prepared pan and bake for 32 to 35 minutes, or until a toothpick inserted near the center comes out with a few moist crumbs but not wet batter.
Cool completely. Let the brownies cool completely in the pan before frosting to ensure the frosting sets properly.
Make the frosting. Beat the 1/2 cup softened butter until smooth, then gradually mix in the 2 cups confectioners’ sugar, 2 to 3 tablespoons reduced Guinness, 1 teaspoon espresso powder, 1/2 teaspoon pure vanilla extract, and 1/4 teaspoon salt until combined and spreadable. Adjust the amount of reduced Guinness to reach your desired consistency.
Frost and serve. Frost the cooled brownies, then cut them into squares. Store leftover brownies at room temperature in an airtight container.

For a different baked pastry idea that celebrates butter and texture, explore the technique used in these Delicious Cruffins with Cinnamon.

Recipe Details

Prep Time: 20 minutes
Cook Time: 35 minutes
Total Time: 55 minutes
Servings: 12 squares
Calories: approximately 560 per serving

Tips, Storage & Variations

Tips: Use room temperature eggs to incorporate air more easily. When reducing Guinness, lower the heat if it splatters. For fudgier brownies, do not overbake and check at 32 minutes.
Storage: Store leftover brownies at room temperature in an airtight container for up to 3 days. Frosted brownies keep best when not refrigerated to preserve a tender texture.
Freezing: Freeze unfrosted brownies wrapped tightly in plastic wrap and foil for up to 3 months. Thaw at room temperature, then frost. Frosted squares can be frozen in a single layer until firm, then stacked with parchment between pieces.
Flavor variations using existing ingredients only:
- Increase espresso powder to 1 teaspoon in the batter for a stronger mocha note.
- Use the higher amount of reduced Guinness in the frosting, 3 tablespoons, for a more pronounced beer flavor.
- Omit the espresso powder for a purer chocolate-beer profile.

Pair these brownies with a contrasting savory course like Flavor-Packed Peruvian Chicken with Aji Verde Cilantro Rice for a memorable menu.

Frequently Asked Questions

Q: Can I skip reducing the Guinness?
A: You can skip reducing, but reduction concentrates flavor and removes some liquid for better brownie texture.

Q: Can I use a different stout or beer?
A: Yes, another stout will work, but flavors may vary. Avoid very light beers.

Q: Is espresso powder necessary?
A: No, it is optional. Espresso powder boosts chocolate depth but can be omitted.

Q: How do I know when brownies are done?
A: A toothpick should come out with moist crumbs, not wet batter. Edges will be set.

Q: Can I make these ahead?
A: Yes, bake and cool the brownies, then frost the next day. Store at room temperature.

Q: What pan size should I use?
A: Use a 9-inch square pan as specified for the correct thickness and bake time.

Conclusion

I hope you enjoy making these Guinness Brownies with Guinness Frosting at home. They are a great blend of fudgy chocolate and rounded malt notes that make a striking dessert for gatherings or a cozy night in. For another take on Guinness brownies, compare techniques on WellPlated’s Guinness brownies, and for more variations and tips, see the recipe at Sally’s Baking Addiction Guinness brownies. If you try this recipe, please share how they turned out and any personal twists you added. Enjoy a warm, delicious bite.