New This Month

Peanut-Butter Swirl Brownies


Dollops of peanut butter filling are spooned onto brownie batter; pulling a knife back and forth through both results in a marbleized look.

  • Yield: Makes 9 large or 16 small squares
peanut butter swirl brownies

Photography: Con Poulos

Source: Martha Stewart Living, February 2004


For the batter

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

For the filling

  • 4 tablespoons unsalted butter, melted
  • 1/2 cup confectioners' sugar
  • 3/4 cup smooth peanut butter
  • 1/4 teaspoon salt
  • 1/2 teaspoon pure vanilla extract


  1. Preheat oven to 325 degrees. Line a buttered 8-inch square baking pan with foil or parchment paper, allowing 2 inches to hang over sides. Butter lining (excluding overhang); set pan aside.

  2. Make batter: Put butter and chocolates in a heatproof medium bowl set over a pan of simmering water; stir until melted. Let cool slightly.

  3. Whisk together flour, baking powder, and salt in a separate bowl, and set aside.

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

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

  6. Pour one-third of batter into prepared pan, and spread evenly with a rubber spatula. Place dollops of filling (about 1 tablespoon each) about 1 inch apart on top of batter. Drizzle remaining batter on top, and gently spread to fill pan. Place dollops of remaining filling on top.

  7. With a butter knife, gently swirl filling into batter, running knife lengthwise and crosswise through layers. Bake until a cake tester inserted into brownies (avoid center and edges) comes out with a few crumbs but is not wet, about 45 minutes. Let cool slightly in pan, about 15 minutes. Lift out brownies; let cool completely on a wire rack before cutting into squares.

Cook's Notes

To swirl brownies, work quickly so that batter and filling don't set. Use two large spoons to drop dollops of filling on the first layer of batter about one inch apart. Repeat with next layer of batter and remaining filling. Drag a butter knife back and forth through the layers with the tip touching the bottom of the pan.

Reviews Add a comment

  • Curlycupcake
    2 JAN, 2014
    The taste of the brownies is good but they crumbled apart on me. I had to bake them 10 minutes longer because they weren't set after I had baked them for the amount of time the recipe called for. When I tried to cut the first brownie it crumbled and I thought it was just because it was the first. But then the next and next crumbled too. I wouldn't make this recipe again.
  • EloiseCS
    1 NOV, 2013
    Personally (don't listen to the others) - this was simply amazing! It was slightly more cake-like compared to a normal chewy brownie, but I preferred that! I edited the recipe a tad too - I doubled the amount of Peanut Butter on top (but I love Peanut Butter), added some milk chop chips on top of the Peanut Butter as well - because I absolutely adore chocolate! I then also added a few spoonful's of Peanut Butter into the chocolate mixture whilst it was melting. They were simply delightful!
  • gross
    12 OCT, 2013
    So disgusting. Don't bother wasting your ingredients. This is not a brownie.
  • tastytastie
    27 JUN, 2013
    It would be nice if Martha took a basic writing class before uploading any more recipes. There should have been two separate ingredient lists: one for the brownies and the other for the topping. As it is now, it is almost impossible to follow. Spend a little less energy being pretentious and a little more being CLEAR. I am sure most bakers are primarily interested in yielding positive results as opposed to reading a fancy web site.
  • ESPK
    18 JUN, 2013
    I wanted to add to my below review that the peanut butter filling portion of this recipe was actually quite good despite the whole brownie not being the best.
  • ESPK
    17 JUN, 2013
    Unfortunately, I wish I had read more of the reviews for this recipe prior to making the brownies. If you like "cakey" brownies, then this is the recipe for you because even if you cut back on the baking time, they're still cakey. This recipe is not worth the time or ingredients that are needed to make it. Furthermore, the recipe is incredibly unclear the way it's written as it pertains to what the measurements of the ingredients are specific to the batter and filling. Very disappointing...
  • PIE Lover
    11 MAR, 2013
    These brownies are chewy and soft. One of the best combo with peanut butter and chocolate, I think.
  • Rebecca Su
    5 MAR, 2013
  • Rachel g
    16 FEB, 2013
    These brownies are, hands down, the BEST I EVER HAD. Anyone who's unsure of making these, just make 'em!
  • momof4boyz
    1 FEB, 2013
    I was in a hurry, so I used Ghiradelli brownie mix and added the M S peanut butter swirl, had to bake an xtra few min, but it was a big hit, very moist and fudgy! cheater, I know ; )