These chocolate-loaded Mississippi Mud Brownies have a brownie base that is topped with peanut butter, marshmallows, pecans, and a light chocolate frosting. Just like the pie!
As my most frequent dining buddy, Marc got nominated as my official taste tester. It doesn’t sound like a rough job, but for a guy who thinks food is “good” or “okay,” sometimes it’s hard getting a lot of feedback from him. Our typical conversation after eating the first couple bites of something I made usually goes something like: 
Me: “So, what do you think?”
Marc: “It’s good”
Me: “No, what do you really think? Does it have enough flavor? It is too dry? Is it blog worthy?”
Marc: “It’s the best meal ever.”
This response doesn’t literally mean that it’s the best meal ever. No, that’s just his cop out and usually his hint that he doesn’t really feel like digging in his brain for any more adjectives. I usually just give up there and move the conversation to something else.
So when he tried these Mississippi Mud Brownies and said “These are the best brownies I have ever had” I thought he was just being a smart ass. It turns out, he was being serious and they really are the best brownies he’s ever had. After eating way too many of these myself, I’m gonna have to agree with the guy. There are just so many layers of deliciousness going on!
The bottom layer is a dense and fudgy brownie which is topped with crunchy peanut butter, marshmallows, and pecans. Then to top it all off there is a thin chocolate frosting that seeps into all of the little crevices between the marshmallows and pecans. If that isn’t the best brownie ever, I don’t know what is.
Click here for the frosting recipe.
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Chocolate-Loaded Mississippi Mud Brownies
- Yield: 16 squares (from an 8×8-inch pan) 1x
Description
These chocolate-loaded Mississippi Mud Brownies have a brownie base that is topped with peanut butter, marshmallows, pecans, and a light chocolate frosting. Just like the pie!
Ingredients
For the brownie layer
- 1/2 cup (1 stick) unsalted butter, at room temperature
- 1 cup white sugar
- 3/4 tsp pure vanilla extract
- 2 eggs
- 3/4 cup all-purpose flour
- 2 tablespoons unsweetened cocoa powder
- 1/2 tsp salt
- 3/4 cup semi-sweet chocolate chips
For the peanut butter layer
- 1/2 cup crunchy peanut butter
- 1 1/2 teaspoons canola oil
For the marshmallow layer
- 2 cups mini marshmallows
For the topping
- 1/2 cup pecans, chopped and toasted
For the chocolate frosting
- 4 tablespoons (1/2 stick) unsalted butter
- 3 tablespoons unsweetened cocoa powder
- 1/4 cup + 2 tablespoons whole milk (divided)
- 2 cups confectioners' sugar, sifted
- Pinch of salt
- 1/2 teaspoon pure vanilla extract
Instructions
- Preheat oven to 350°F. Line an 8×8-inch square baking pan with parchment paper or foil. If using foil, spray with cooking spray.
- In a medium bowl, whisk together the flour, cocoa powder, and salt. Set aside.
- In a large mixing bowl, beat together the butter, sugar, and vanilla until creamy. Add the eggs one at a time, beating after each.
- Stir the dry ingredients into the batter until combined. Pour into the prepared pan and spread evenly. Sprinkle with chocolate chips.
- Bake for 22–25 minutes.
- While the brownie is baking, combine the peanut butter and canola oil in a microwave-safe bowl and microwave on high for 20 seconds to soften.
- Remove the brownie from the oven. Pour the warm peanut butter mixture evenly over the hot brownie layer and spread gently.
- Sprinkle the marshmallows over the peanut butter layer. Return to the oven for 3 more minutes, until the marshmallows puff.
- Remove from the oven and sprinkle immediately with the toasted pecans.
Make the frosting
- In a small saucepan, melt the butter over medium heat. Add the cocoa powder and ¼ cup of the milk and heat, stirring, until the mixture just begins to boil.
- Remove from heat. Pour into a mixing bowl with the sifted confectioners’ sugar and a pinch of salt. Beat on high speed with an electric mixer until smooth and glossy.
- If the frosting is not pourable, add the remaining 2 tablespoons of milk and beat again.
- Beat in the vanilla extract. Pour the frosting evenly over the puffed marshmallow and pecan layer.
- Refrigerate for 1–2 hours until completely set. Cut into squares and serve.
Notes
The frosting is intentionally thin and pourable — it seeps into all the gaps between the marshmallows and pecans, which is exactly what you want. Refrigerate until fully set before cutting for clean squares.
- Category: Baking, Dessert
Frequently Asked Questions
What type of peanut butter should I use for the Mississippi Mud Brownies?
You can use creamy or crunchy peanut butter, depending on your texture preference. Just ensure it’s a good quality peanut butter for the best flavor.
How can I prevent the marshmallows from melting completely on top of the brownies?
To keep the marshmallows from melting too much, add them to the brownies during the last few minutes of baking, allowing them to puff up without losing their shape.
Can I substitute the pecans with another type of nut?
Yes, you can substitute pecans with walnuts or almonds if you prefer, but keep in mind that it will slightly change the flavor and texture of the brownies.
These look so delicious can’t wait to make it.