Mississippi Mud Bars are rich, chewy dessert bars packed with layers of chocolate, peanut butter, and toasted pecans. The soft, brownie-like base is loaded with chunks of semisweet and white chocolate, then topped with a marbled chocolate finish that melts beautifully over the warm bars. With their deep chocolate flavor and satisfying crunch from pecans, these bars are a decadent treat perfect for gatherings, holidays, or whenever you want an indulgent homemade dessert.
Why You’ll Love This Recipe
Rich and indulgent with layers of chocolate flavor
Chewy texture with a slightly soft center
Simple ingredients that are easy to find
Perfect for parties, bake sales, and family desserts
The marbled chocolate topping makes them look impressive with minimal effort
Great balance of sweetness from chocolate and nuttiness from pecans
Easy to cut into squares for serving and sharing
Ingredients
(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)
1 stick (113 g) unsalted butter, softened
1 cup (200 g) packed brown sugar
½ cup (130 g) creamy peanut butter
1 large egg, room temperature
1 tablespoon pure vanilla extract
1 cup (125 g) all-purpose flour
½ teaspoon baking soda
½ teaspoon salt
2 ounces (56 g) white chocolate, coarsely chopped and divided
8 ounces (226 g) semisweet chocolate, coarsely chopped and divided
1 cup (120 g) toasted pecans, coarsely chopped and divided
Directions
Preheat the oven to 325°F (165°C). Lightly grease an 8-inch or 9-inch square baking pan.
In a large mixing bowl, beat the softened butter and brown sugar using an electric mixer on medium speed until creamy and smooth.
Add the peanut butter and continue mixing until fully combined and smooth.
Add the egg and vanilla extract, beating until the mixture becomes well blended.
In a separate bowl, whisk together the flour, baking soda, and salt.
Gradually add the dry ingredients to the butter mixture and mix until a smooth batter forms.
Stir in half of the chopped white chocolate and half of the semisweet chocolate.
Fold in half of the chopped toasted pecans and mix until evenly distributed.
Spread the batter evenly into the prepared baking pan.
Bake for 25 to 30 minutes, until the center is soft but no longer runny.
Remove the pan from the oven and immediately sprinkle the remaining white and semisweet chocolate over the hot bars.
Cover the pan loosely with aluminum foil and allow the chocolate to melt for several minutes.
Once melted, use the tip of a knife to gently swirl the chocolates together to create a marbled pattern.
Sprinkle the remaining chopped pecans evenly over the top.
Allow the bars to cool completely in the pan on a wire rack.
Cut into approximately 2-inch squares before serving.
Servings and timing
Servings: 16 bars
Preparation time: 10 minutes
Cooking time: 25–30 minutes
Cooling time: 45–60 minutes
Total time: about 1 hour 30 minutes
Variations
Chocolate Lover’s Version
Add an extra 2 ounces of chopped semisweet chocolate into the batter for an even richer chocolate flavor.
Nut-Free Option
Replace the pecans with additional chocolate chunks or omit them entirely if you prefer a nut-free dessert.
Peanut Butter Swirl
Drop small spoonfuls of extra peanut butter over the batter before baking and swirl lightly with a knife.
Caramel Addition
Drizzle caramel sauce over the melted chocolate layer before it sets for a sweet and buttery twist.
Crunchy Texture
Replace creamy peanut butter with crunchy peanut butter for added texture in the bars.
Storage/Reheating
Room Temperature
Store the bars in an airtight container at room temperature for up to 3 days.
Refrigerator
For longer storage, keep them refrigerated in a sealed container for up to 1 week.
Freezer
Wrap the bars individually or place them in a freezer-safe container and freeze for up to 2 months. Thaw at room temperature before serving.
Reheating
If you prefer them slightly warm, microwave a bar for about 10–12 seconds to soften the chocolate and enhance the flavor.
FAQs
Can I use a different type of nut?
Yes, walnuts or almonds can be used instead of pecans while still providing a nice crunch.
Can I make these bars ahead of time?
Yes, they can be prepared a day in advance and stored in an airtight container until ready to serve.
How do I know when the bars are done baking?
The center should look set but still soft. A toothpick inserted near the center should come out with a few moist crumbs.
Can I use chocolate chips instead of chopped chocolate?
Yes, chocolate chips can be substituted for convenience, though chopped chocolate melts more smoothly.
What size pan works best?
An 8-inch pan will give slightly thicker bars, while a 9-inch pan will produce thinner bars.
Why cover the pan with foil after adding the chocolate?
The foil traps heat so the chocolate melts evenly, making it easy to swirl.
Can I reduce the sugar?
You can slightly reduce the brown sugar by about 2 tablespoons, but reducing too much may affect the texture.
Can these bars be made gluten-free?
Yes, substitute the all-purpose flour with a gluten-free baking flour blend designed for 1:1 replacement.
Do the bars need to be refrigerated?
They do not need refrigeration for short-term storage but will last longer if kept chilled.
Can I double the recipe?
Yes, double the ingredients and bake in a 9×13-inch pan. The baking time may increase slightly.
Conclusion
Mississippi Mud Bars are a wonderfully indulgent dessert combining peanut butter, rich chocolate, and crunchy pecans in every bite. Their chewy base and marbled chocolate topping create a treat that is both visually appealing and irresistibly delicious. Whether you are baking for a special occasion or simply craving a homemade sweet, these bars are sure to become a favorite in your dessert collection.
Rich, chewy dessert bars packed with layers of chocolate, peanut butter, and toasted pecans, topped with a marbled melted chocolate finish for an indulgent treat perfect for gatherings and holidays.
Ingredients
1 stick (113 g) unsalted butter, softened
1 cup (200 g) packed brown sugar
1/2 cup (130 g) creamy peanut butter
1 large egg, room temperature
1 tablespoon pure vanilla extract
1 cup (125 g) all-purpose flour
1/2 teaspoon baking soda
1/2 teaspoon salt
2 ounces (56 g) white chocolate, coarsely chopped and divided
8 ounces (226 g) semisweet chocolate, coarsely chopped and divided
1 cup (120 g) toasted pecans, coarsely chopped and divided
Instructions
Preheat the oven to 325°F (165°C). Lightly grease an 8-inch or 9-inch square baking pan.
In a large mixing bowl, beat the softened butter and brown sugar with an electric mixer on medium speed until creamy and smooth.
Add the peanut butter and mix until fully combined.
Add the egg and vanilla extract and beat until well blended.
In a separate bowl, whisk together the flour, baking soda, and salt.
Gradually add the dry ingredients to the butter mixture and mix until a smooth batter forms.
Stir in half of the chopped white chocolate and half of the semisweet chocolate.
Fold in half of the chopped toasted pecans.
Spread the batter evenly into the prepared baking pan.
Bake for 25–30 minutes until the center is soft but no longer runny.
Remove the pan from the oven and immediately sprinkle the remaining white and semisweet chocolate over the hot bars.
Cover the pan loosely with aluminum foil and allow the chocolate to melt for several minutes.
Use the tip of a knife to gently swirl the melted chocolates together to create a marbled pattern.
Sprinkle the remaining chopped pecans evenly over the top.
Allow the bars to cool completely on a wire rack.
Cut into approximately 2-inch squares before serving.
Notes
An 8-inch pan produces thicker bars, while a 9-inch pan gives thinner bars.
Chocolate chips can be used instead of chopped chocolate if preferred.
Do not overbake; the center should remain slightly soft for the best chewy texture.
Covering the pan with foil helps melt the chocolate evenly for easy swirling.
Allow bars to cool fully before cutting to keep clean edges.
