Old Fashioned Mississippi Mud Pie is a deeply chocolatey, Southern dessert with a crumbly cookie crust, a fudgy brownie-like filling, and a thick layer of marshmallow and chocolate ganache on top. It gets its name from the dense, dark, mud-like texture of the filling, and it’s served chilled or at room temperature in generous slices. This recipe works because it layers simple, reliable components—a buttery chocolate wafer crust, a rich brownie base, and a glossy ganache—into one indulgent pie that slices cleanly and tastes even better the next day.
Ingredients
- For the crust:
- 1 1/2 cups (170 g) chocolate wafer crumbs (about 30 wafers) or 1 1/2 cups (170 g) graham cracker crumbs mixed with 2 tbsp (15 g) cocoa powder
- 6 tbsp (85 g) unsalted butter, melted
- 2 tbsp (25 g) granulated sugar
- Pinch of salt
- For the brownie filling:
- 1/2 cup (115 g) unsalted butter, melted
- 1 cup (200 g) granulated sugar
- 2 large eggs, at room temperature
- 1 tsp vanilla extract
- 1/2 cup (60 g) all-purpose flour
- 1/3 cup (30 g) unsweetened cocoa powder
- 1/4 tsp salt
- 1/2 cup (90 g) semisweet chocolate chips (optional, for extra fudginess)
- For the marshmallow layer:
- 2 cups (100 g) mini marshmallows
- For the chocolate ganache topping:
- 1 cup (240 ml) heavy cream
- 1 1/2 cups (255 g) semisweet or bittersweet chocolate chips
- 2 tbsp (30 g) unsalted butter, softened
- 1 tsp vanilla extract
Instructions
- Preheat your oven to 350°F (175°C). Lightly grease a 9-inch (23 cm) pie dish or a 9-inch springform pan.
- Make the crust: In a medium bowl, combine the chocolate wafer crumbs, melted butter, sugar, and salt. Stir until the crumbs are evenly moistened. Press the mixture firmly into the bottom and up the sides of the prepared dish. Use the bottom of a flat measuring cup to compact it well.
- Bake the crust for 10 minutes. Remove from the oven and set aside to cool slightly while you make the filling. Leave the oven on.
- Make the brownie filling: In a large bowl, whisk together the melted butter and sugar until smooth. Add the eggs one at a time, whisking well after each addition. Stir in the vanilla.
- Sift the flour, cocoa powder, and salt over the wet ingredients. Fold gently with a spatula until just combined—do not overmix. If using chocolate chips, fold them in now.
- Pour the brownie batter into the prepared crust and spread it evenly. Bake for 25–30 minutes, until the top is set and a toothpick inserted 2 inches from the edge comes out with a few moist crumbs. The center should still look slightly underdone; it will continue to set as it cools.
- Remove the pie from the oven and immediately sprinkle the mini marshmallows evenly over the hot brownie layer. Return the pie to the oven for 2–3 minutes, just until the marshmallows puff up slightly. Do not let them brown too much. Remove and let cool completely on a wire rack, about 1 hour.
- Make the ganache: In a small saucepan, heat the heavy cream over medium heat until it just begins to simmer (you’ll see small bubbles around the edges). Remove from heat and add the chocolate chips. Let sit for 2 minutes, then add the butter and vanilla. Stir slowly until the mixture is smooth and glossy. If any lumps remain, place the pan back over low heat for 30 seconds and stir again.
- Pour the ganache over the cooled marshmallow layer, spreading it gently to cover completely. Refrigerate the pie for at least 2 hours, or until the ganache is firm and set.
- To serve, let the pie sit at room temperature for 15–20 minutes for easier slicing. Use a sharp knife dipped in hot water and wiped dry between cuts.
Tips
- Substitutions: If you can’t find chocolate wafer cookies, use graham crackers and add 2 tablespoons of cocoa powder to the crumbs. For a gluten-free version, use gluten-free chocolate cookies or a gluten-free flour blend in the brownie layer—the texture will be slightly more crumbly but still delicious.
- Don’t overbake the brownie layer: The filling should be fudgy, not cakey. Pull it out when the edges are set and the center jiggles slightly. It will continue to cook from residual heat as it cools.
- Chill before slicing: The pie needs at least 2 hours in the fridge after the ganache is added. If you slice it too soon, the layers will run together. For the cleanest slices, chill for 4 hours or overnight.
- Common mistake: Pouring hot ganache over marshmallows that are still warm can cause the marshmallows to melt and disappear. Make sure the pie is completely cool before adding the ganache.
Serving Suggestions
Serve this pie in small slices—it’s rich. A dollop of lightly sweetened whipped cream or a scoop of vanilla ice cream balances the deep chocolate. For a Southern touch, add a drizzle of warm caramel or a sprinkle of toasted pecans. Pair with strong coffee or cold milk.
Variations
- Peanut Butter Mississippi Mud Pie: Add 1/2 cup (130 g) creamy peanut butter to the brownie batter, and swirl extra peanut butter into the ganache.
- Mint Chocolate: Add 1/2 teaspoon peppermint extract to the brownie batter and substitute mint chocolate chips for the semisweet in the ganache.
- Bourbon or Coffee: Stir 2 tablespoons of bourbon or cooled espresso into the brownie batter for an adult twist.
- No-Bake Version: Skip the brownie layer and use a prepared chocolate pudding mix for a quick, no-oven version, though the texture will be creamier and less fudgy.
Storage and Reheating
Store leftover pie covered in the refrigerator for up to 4 days. The crust will soften slightly over time, which is normal. To freeze, wrap the fully chilled pie (without whipped cream) tightly in plastic wrap and then foil; freeze for up to 3 months. Thaw overnight in the refrigerator before serving. To reheat individual slices, microwave for 15–20 seconds to soften the ganache and brownie, but be careful not to melt the marshmallows into a puddle. For a firmer texture, serve cold straight from the fridge.
Frequently Asked Questions
Can I use a store-bought pie crust?
Yes, a store-bought chocolate cookie crust or a regular graham cracker crust works. If using a standard 9-inch graham crust, reduce the butter to 4 tablespoons and skip the sugar, as the crust is already sweet.
Why is my ganache lumpy?
Lumps usually happen if the cream was too hot or the chocolate was added too quickly. To fix it, warm the mixture gently over a double boiler, stirring constantly until smooth. If it’s still lumpy, strain it through a fine-mesh sieve.
Can I make this pie ahead of time?
Absolutely. This pie is actually better when made a day ahead. Prepare it completely, cover, and refrigerate overnight. The flavors meld and the texture firms up, making it easier to slice.
Do I need to use a springform pan?
No, a regular 9-inch pie dish works perfectly. If you want to remove the pie for serving, line the dish with parchment paper or use a springform pan. A pie dish is easier for casual serving.
Can I skip the marshmallows?
Yes, you can omit them for a simpler mud pie. The ganache will sit directly on the brownie layer, which is still delicious. Some people prefer this version because it’s less sweet.
Why does my pie crack on top?
Overbaking is the usual culprit. The brownie layer should be slightly underdone in the center. Also, cooling the pie gradually (not putting it in the fridge while hot) helps prevent cracking.
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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes
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