Rich, dark brownies topped with marshmallows, pecans, and luscious chocolate fudge frosting.

Mississippi Mud Brownies

I’ve tried numerous Mississippi Mud Brownie recipes and ordered them at restaurants. They’re all too sweet and the frosting tends to be sugary and grainy. This recipe is a gamechanger! I made these brownies for a reception and watched grown men swoon at the first bite.
Prep batter: 40 minutes Bake: 25 minutes Bake at: 350°F Yield: 24 Pan: 9x13-inch baking pan Prep frosting: 35 minutes Difficulty: easy

Ingredients

Brownie Batter

  • 1 1/2 cups pecans, chopped (no substitute)
  • 2 cups (12 ounces) semi-sweet chocolate chips
  • 3/4 cup (1 1/2 sticks) unsalted butter
  • 1 cup agave nectar or maple syrup
  • 1/3 cup (67 grams) granulated sugar
  • 3 large eggs, room temperature
  • 1 tablespoon vanilla extract
  • 1 cup (120 grams) all-purpose flour, sifted
  • 1/2 teaspoon salt
  • 10-ounce bag mini marshmallows
  • Non-Stick cooking spray

Chocolate Fudge Frosting

  • 4 ounces Baker’s unsweetened chocolate squares, chopped
  • 3 ounces Baker’s dark chocolate squares, chopped
  • 1/2 cup (1 stick) unsalted butter
  • 1/2 cup (100 grams) granulated sugar
  • 1/2 cup heavy whipping cream
  • 2 teaspoons instant coffee granules (optional)
  • 2 teaspoons vanilla extract
  • 1 2/3 cup (187 grams) powdered sugar, sifted

Directions

Making the Brownies

Top hot brownies with marshmallows and pecans before you finish baking the brownies.
  • Preheat the oven to 350°F.
  • Chop the pecans and set aside.
  • Pour the chocolate chips into a large bowl. Heat the butter in a medium saucepan over medium heat until it is just melted; do not boil. Pour the butter over the chocolate chips and let stand until the chips are soft, about 3 minutes. Starting from the center, gently whisk together the ingredients until smooth. Let the mixture stand for 10 minutes until it is barely lukewarm.
  • Add the agave nectar or maple syrup to the bowl, along with the sugar, and whisk together. Whisk in the eggs, one at a time, and then the vanilla. Sift the flour and salt into the bowl and whisk until just smooth.
  • Prepare the pan with non-stick cooking spray. Spread the brownie batter evenly into the pan.
  • Bake the brownie for 22 minutes and remove the pan from the oven. Spread the marshmallows across the top of the brownies. Sprinkle the pecans over the marshmallows. Return the pan to the oven and bake 3 more minutes.
  • Let the brownies cool in their pan on a wire rack for 45 minutes before preparing the frosting.

Making the Chocolate Fudge Frosting

Chocolate fudge frosting beaten until smooth and ready to spread over brownies.
  • Chop the unsweet and dark chocolate squares and place them in a medium bowl.
  • In a medium saucepan, combine the butter, sugar, cream, and coffee granules, if using. Stir the mixture over medium heat until the sugar and coffee granules fully dissolve and the mixture comes to a simmer; do not boil. Pour the butter mixture over the chocolate. Let the mixture cool for 2 minutes and then gently whisk the ingredients together until smooth. Add the vanilla and whisk.
  • Add the powdered sugar to the chocolate mixture. Using an electric mixer, beat the powdered sugar into the chocolate mixture until the frosting is shiny and very smooth, about 3 minutes. You should not see sugar granules. Pour the frosting over the brownies and spread evenly (see “Tips”).
  • Refrigerate the brownies in the pan for about 1 hour until the frosting hardens; slice and serve.
  • You can cover and store the brownies at room temperature for up to 4 days or freeze individually wrapped pieces for up to 3 weeks.

Tips

Do not refrigerate the frosting before using. It hardens quickly and will not be spreadable.
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