Herbie Likes Spaghetti: St. Patrick's Day Treat: Peanut Butter Swirled Guinness Brownies

Happy St Patrick's Day! In honor of this special day of corned beef, cabbage, and green beer, we're bringing you something sweet and delicious - Peanut Butter Swirled Guinness Brownies! We don't make a ton of sweets around these parts, but when we do, we go big.

We served these brownies up sundae style with some delicious homemade vanilla ice cream. This recipe was adapted from Brown Eyed Baker's Peanut Butter Brownies and Patent and the Pantry's Guinness Brownies.

Making the Dessert
What You'll Need

For the Guinness Brownies

1 cup all-purpose flour

1 teaspoon salt

3/4 cup unsweetened cocoa powder

8 ounces dark bittersweet chocolate

8 ounces unsalted butter, cut into 1-inch pieces

1 cup granulated sugar

1/2 cup packed light brown sugar

4 eggs

2 bottles guinness beer, reduced to 1 1/4 cups

2 teaspoons vanilla extract

For the Peanut Butter Swirl

8 tablespoons unsalted butter, melted

3/4 cup powdered sugar

1 cup creamy peanut butter

1/2 teaspoon salt

1 teaspoon vanilla extract

Pour both bottles of Guinness into a medium saucepan, and simmer on medium heat until it's reduced down to 1 1/4 cups. This should take about 15 minutes. It'll smell a little weird, but it's worth it. When complete, remove the Guinness from heat and let cool.

Preheat the oven to 350 degrees. Butter the sides and bottom of a 9×13-inch glass or light-colored baking pan.

In a medium bowl, whisk together flour, cocoa powder, and salt.

Put the chocolate and butter in a saucepan over very low heat, stirring occasionally, until the chocolate and butter are completely melted and smooth. Turn off the heat and add the sugars. Whisk until completely combined.

Add 4 eggs to the chocolate mixture and whisk until combined. Add the vanilla and stir until combined. Make sure that you don't overbeat the batter or you'll end up with cakey brownies, rather than nice fudgey brownies.

Sprinkle the flour mixture over the chocolate mixture and fold the flour mixture into the chocolate until just a bit of the flour mixture is visible. For this part, use a spatula instead of a whisk. Finally, stir in the cooled reduced Guinness until it is completely incorporated.

Pour the batter into the baking pan and smooth the top with your spatula.

Next make the peanut butter swirl by simply mixing together all of the peanut butter swirl ingredients. Then place dollops of the peanut butter mixture all over the top of the brownie batter. Using a butter knife, swirl the chocolate and peanut butter, using a knife to incorporate the peanut butter mixture into a nice design across the Guinness brownie batter.

Place the brownies in the center of the oven for 30 minutes. Let the brownies cool completely. Cut into squares and serve.

If you're feeling really decadent, do what we did and serve it with some vanilla ice cream, whip cream, and hot fudge. You'll be glad you did!

The Result

These brownies will certainly not disappoint. They're not overwhelmingly "beery" - just a simple hint of that nice dark Guinness flavor. The peanut butter swirl on top is a delight, and gives it a rich, salty sweet contrast to the deep chocolate flavor of the Guinness brownies.