Peanut Butter Swirl Brownies

by Katie on May 26, 2011

I purchased some new cookbooks on my most recent trip to Sam’s club.

(I can get into some serious trouble at that place.)

The cookbook section beckons me upon entering the store. The supply is always changing and I just can’t resist.

This particular day I skimmed the sections looking for it. Yay! I found it. Something I had been eying for some time now.

Martha Stewart’s Cupcakes

Be still my heart.

I let out a little squeal and jump for joy. I hugged it and refused to leave it behind. I was in luck, because they also had her pies and tarts and cookie cookbook.

My husband insisted that I buy the cookie one too. Wasn’t that nice of him?  I sure thought so.

(He was being nice, but I think he also like me to bake for him…so buying me new cookbooks helps!)

I came home and began flagging both cookbooks. I am obsessed with those little page flagger things.  LOVE THEM.  I flag every cookbook with recipes that are a must try.

This was the first recipe I tried from the cookie cookbook…and I made them that evening.  I just couldn’t wait!!!

I love chocolate, but I love peanut butter just as much.  There are no wimpy peanut butter swirls in these babies.


There is A LOT of peanut butter. A sufficient taste in every bite. So, if you are like me and like them both equally you need to run, not walk, to the kitchen and bake these up!


for the batter:
1/2 cup (1 stick) unsalted butter, cut into small pieces, plus more for pan
2 ounces unsweetened chocolate, coarsely chopped
4 ounces semisweet chocolate, coarsely chopped
2/3 cup all-purpose flour
1/2 teaspoon baking powder
1/4 teaspoon coarse salt
3/4 cup granulated sugar
3 large eggs
2 teaspoons vanilla extract

for the filling:
4 tablespoons (1/2 stick) unsalted butter, melted
1/2 cup confectioners’ sugar
3/4 cup smooth peanut butter
1/4 teaspoon coarse salt
1/2 teaspoon vanilla extract


Preheat oven to 325 degrees. Butter an 8-inch square baking pan and line with parchment, allowing a 2-inch overhang. Butter lining (not overhang).

Make batter: Put butter and chocolates in a heatproof medium bowl set over a pan of simmering water; stir until melted. Let cool slightly. Whisk together flour, baking powder, and salt in a bowl.

Whisk granulated sugar into chocolate mixture. Add eggs, and whisk until mixture is smooth. Stir in vanilla. Add flour mixture; stir until well combined.

Make filling: Stir together butter, confectioners’ sugar, peanut butter, salt, and vanilla in a bowl until smooth.

Pour one-third of batter into prepared pan; spread evenly with a rubber spatula. Drop dollops of peanut butter filling (about 1 tablespoon each) on top of batter, spacing about 1 inch apart. Drizzle remaining batter on top, and gently spread to fill pan. Drop dollops of remaining peanut butter mixture on top. Gently swirl peanut butter filling into batter with a butter knife, running the knife lengthwise and crosswise through layers.

Bake until a cake ester inserted into brownies (avoid center and edges) comes out with a few crumbs but is not wed, about 45 minutes. Let cool slightly in pan, about 15 minutes. Life out; let cool completely on a wire rack before cutting into squares. Brownies can be stores in an airtight container at room temperature up to 3 days.

{ 10 comments… read them below or add one }

Tina (Tightwad Mom) May 26, 2011 at 8:37 pm

Katie, I KNEW you were a “kindred spirit”. I LOVE cookbooks (always have to check them out at Costco), brownies, and peanut butter. I can’t wait to try this recipe. Yum!!!


Katie May 26, 2011 at 11:59 pm

Oh, Tina…you will LOVE these! They are so peanut buttery :)


Bitterroot Mama May 27, 2011 at 10:12 am

MMMM. I love cookbooks. And brownies. And peanut butter. And posting redundant comments. Have fun marking the cookbooks up!


Katie May 27, 2011 at 11:10 am

You are so funny! I sure will have fun marking them up…I just can’t resist!!


Elise Gabrielle (One Day I Will Be) May 28, 2011 at 1:54 pm

Katie! This sounds wonderful! Sadly, I’m allergic to peanuts (consumption wise), but I will have to make these for my peanut-aholic boyfriend! Thanks so much for the recipe! I have been trying to help my mom out in the kitchen more and expand my cooking repertoire and let me tell you, your recipes tab is really helping me out! ;] Hope all is well!


Katie May 31, 2011 at 3:19 pm

My mom is allergic to peanuts, too. I feel so bad for you guys…I can’t imagine a world without peanut butter ;)

Oh, and good for you helping your mom out, I’m sure she really appreciates your help!


Tiffanee May 28, 2011 at 11:42 pm

Oh I love that flavor combination. Gotta love new cookbooks. Love the flagging idea!!


Katie May 31, 2011 at 3:20 pm

Yes, Tiffanee…it is so hard to keep track of all of the recipes you want to make. Flagging really helps!!


Misty May 31, 2011 at 2:41 pm

Whoa! These look downright YUMMY! I am going to have to make these for dessert night this week… Thank you SO much for sharing this yummy recipe.


Katie May 31, 2011 at 3:20 pm

Misty, they sure are downright yummy ;)


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