Introduction

These Dark Chocolate Guinness Brownies with Buttercream offer a rich, indulgent treat with a unique twist from the Guinness reduction and espresso powder. They are fudgy, flavorful, and topped with a luscious, fluffy buttercream that perfectly complements the deep chocolate notes.

Ingredients

½ cup unsalted butter
6 ounces dark baking chocolate (2 bars)
1 ½ cups granulated sugar
12 ounces Guinness beer (1 bottle or can)
1 teaspoon vanilla extract
3 eggs
½ teaspoon espresso powder
1 cup all-purpose flour
½ cup softened butter (for buttercream)
2 cups powdered sugar
½ teaspoon espresso powder (for buttercream)

Instructions

Step 1: Preheat your oven to 350°F. Grease and flour a 9×9-inch baking dish to prepare for the batter.
Step 2: Pour the Guinness into a saucepan over high heat. Let it reduce until about 2/3 cup remains, which takes roughly 10-12 minutes. Transfer this reduction to a heat-safe liquid measuring cup and allow it to cool for at least 15 minutes.
Step 3: While the reduction cools, melt the dark chocolate and ½ cup butter in a microwave-safe bowl. Heat in 30-second increments, stirring well between each until smooth. Mix in the sugar, eggs, vanilla, and ½ cup of the cooled Guinness reduction. Stir in the espresso powder, a pinch of salt, and flour until just combined, taking care not to overmix. The batter will be thick.
Step 4: Pour the batter into the prepared baking dish and bake for 30-35 minutes. Check doneness by inserting a toothpick — it should come out with wet crumbs but no raw batter. If it’s too wet, continue baking in 3-minute increments. Once done, cool the brownies on a wire rack for at least 2 hours until fully cooled.
Step 5: To make the buttercream, beat the softened butter with a mixer until smooth and lump-free. Gradually mix in the powdered sugar and espresso powder until thick and dense. Slowly add the remaining Guinness reduction, one tablespoon at a time, beating until the buttercream becomes light and fluffy.
Step 6: Spread the buttercream evenly over the cooled brownies. Cut into squares and serve.

Tips & Variations

For a deeper coffee flavor, increase the espresso powder slightly in both the batter and buttercream.
Use a sharp knife warmed in hot water to cut the brownies cleanly without tearing the frosting.
If you prefer, substitute stout beer other than Guinness for a similar malt richness.
To make ahead, store the brownies unfrosted and frost just before serving for the freshest texture.

Storage

Store the frosted brownies in an airtight container at room temperature for up to 3 days. For longer storage, keep them in the refrigerator for up to a week; bring to room temperature before serving for the best texture. Brownies also freeze well without frosting—wrap tightly and freeze for up to 3 months.

How to Serve

A stack of three square pieces of dark chocolate cake with a thick layer of light tan frosting on top of each piece, showing a soft and moist texture in the cake and a creamy, slightly grainy texture in the frosting. The bottom two pieces are lying flat, while the top piece is slightly tilted, showing its rich chocolate inside and smooth frosting above. The cake stack is placed on a wire cooling rack over a white marbled surface. In the background, there is a black can with gold and white details, slightly blurred. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use regular chocolate instead of dark baking chocolate?

Yes, but dark baking chocolate offers a richer, more intense flavor that balances well with the Guinness. Using regular chocolate may result in a sweeter, lighter flavor.

Is it necessary to reduce the Guinness before adding it to the batter?

Reducing the Guinness concentrates its flavor and removes excess liquid to prevent the batter from becoming too runny. It also adds a subtle caramelized note to the brownies.