Guinness Brownies with Irish Cream Frosting

These incredibly fudgy Guinness Brownies with Irish Cream Frosting are the ultimate St. Patrick’s Day indulgence! Rich, dense, and intensely chocolatey with a silky boozy frosting—no beer taste, just deep chocolate flavor. Perfect for St. Patrick’s Day celebrations!

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Course: Dessert

Cuisine: American, St. Patrick's Day

Keyword: Guinness Brownies with Irish Cream Frosting

Prep Time: 20

Servings: brownies

Calories: 394kcal

Equipment

9x9-inch baking pan

Ingredients

Wet Ingredients (Brownies):

1 cup (2 sticks) unsalted butter cut into pieces
1¼ cups granulated sugar
¾ cup Guinness stout or other dark stout
2 teaspoons pure vanilla extract
2 large eggs room temperature

Dry Ingredients (Brownies):

¾ cup unsweetened Dutch-process cocoa powder
1 cup all-purpose flour
¼ teaspoon fine sea salt

Mix-ins (Optional):

½ cup semi-sweet chocolate chips

Irish Cream Frosting:

½ cup (1 stick) unsalted butter softened to room temperature
3 cups powdered sugar sifted
2-3 tablespoons Bailey's Irish Cream adjust to taste; 3 tablespoons gives a stronger flavor
1 teaspoon pure vanilla extract
Pinch fine sea salt
1-2 tablespoons heavy cream if needed

For Garnish (Optional):

Chocolate shavings or cocoa powder for dusting
Gold sprinkles or sanding sugar
St. Patrick's Day themed sprinkles

Instructions

Preheat and prepare: Position oven rack in the center of the oven and preheat to 350°F. Line a 9x9-inch baking pan with parchment paper, leaving overhang on two sides for easy removal. Lightly grease the parchment.
Melt butter and add sugar and cocoa: In a medium saucepan, melt the butter over medium heat. Remove from heat and whisk in the sugar until combined. Add the cocoa powder and whisk until smooth and glossy.
Add Guinness (or other Stout beer): Pour in the Guinness and whisk until combined—it will foam up slightly, which is normal.
Add eggs and vanilla: Let the mixture cool for 5 minutes (you don't want to scramble the eggs). Whisk in the vanilla, then add the eggs one at a time, whisking well after each addition until the batter is smooth.
Add dry ingredients: Add the flour and salt directly to the saucepan. Using a spatula or wooden spoon, stir until just combined—do not overmix. Fold in the chocolate chips if using.
Bake: Pour the batter into the prepared pan and spread evenly. Bake for 35-40 minutes, until the top is set and a toothpick inserted in the center comes out with moist crumbs (not wet batter). For fudgier brownies, pull them at 35 minutes. The brownies will continue to set as they cool.
Cool completely: Let the brownies cool in the pan on a wire rack for at least 1 hour before frosting. For cleaner cuts, refrigerate for 30 minutes after cooling.
Make the frosting: In a large bowl, beat the softened butter with an electric mixer on medium speed until light and fluffy, about 2 minutes. With the mixer on low, gradually add the sifted powdered sugar, about 1 cup at a time, beating well after each addition.
Add Bailey's and flavorings: Add the Bailey's (start with 2 tablespoons for a subtle flavor or use 3 tablespoons for a stronger taste), vanilla, and salt. Beat on medium-high for 2-3 minutes until light and fluffy. If the frosting is too thick, add heavy cream 1 tablespoon at a time until you reach your desired consistency.
Frost and garnish: Spread the frosting evenly over the cooled brownies using an offset spatula. For a rustic look, create swirls with the back of a spoon. Top with chocolate shavings, a light dusting of cocoa powder, gold sprinkles or green sanding sugar for a festive touch.
Slice: Use the parchment overhang to lift the brownies from the pan, then slice into squares with a sharp knife.
STORAGE:
Store unfrosted brownies covered at room temperature for up to 3 days or frozen for up to 3 months. Frosted brownies keep in an airtight container in the refrigerator for up to 5 days. Bring to room temperature for 15-20 minutes before serving.

Notes

ANGELA'S TIPS
Will these brownies taste like beer: Not at all! The baking process transforms the stout—you won't taste beer, but you'll notice the brownies are extra moist with a deeper, more complex chocolate flavor. Even people who don't like beer love these brownies.
What if I don't have Guinness: Any dark stout will work well. In a pinch, you can substitute ¾ cup strong brewed coffee for a similar depth of flavor without the stout.
How do I know when the brownies are done: The top should look set and slightly crackled, and a toothpick inserted in the center should come out with moist crumbs—not wet batter, but not completely clean either. When in doubt, pull them earlier.
Can I make a non-alcoholic version of the frosting: Yes! Replace the Bailey's with 3 tablespoons of Irish cream-flavored coffee creamer, or use 2 tablespoons heavy cream plus 1 teaspoon vanilla extract and ¼ teaspoon instant espresso powder.
How do I get clean brownie cuts: Chill the frosted brownies in the refrigerator for 30 minutes before cutting. Use a sharp knife and wipe the blade clean between each cut. For the cleanest edges, run the knife under hot water and dry it before each slice.
Can I use a different pan size: Yes! I tested all three sizes and the 9x9 was the best fit, but other sizes work too. For a 9x13 pan, bake for 25-30 minutes for thinner brownies. For an 8x8 pan, bake for 40-45 minutes for extra thick, fudgy brownies.

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