Recipe for Heavenly Hash Cake with Pecans

What Is Heavenly Hash Cake?

Heavenly hash cake is a Southern-style chocolate sheet cake built around three recognizable elements: a dense, moist chocolate base, nuts—usually pecans—and a marshmallow-and-chocolate finish. This version lands between a fudgy brownie and a conventional snack cake, making it sturdy enough for a 9-by-13-inch pan while remaining tender.

• The mini marshmallows are added after the cake bakes so they puff and soften without vanishing.
• A warm, pourable chocolate icing settles over the marshmallow layer and firms into a soft finish.
• The name also describes New Orleans-style candy and fruit-based desserts; this recipe is specifically the oven-baked cake.

Why These Chocolate Cake Ingredients Matter

Melted butter, sugar, eggs, and cocoa create the cake’s rich, brownie-like character. The flour and modest amount of baking powder provide enough structure to support the toppings without turning the crumb airy or dry. Chopped pecans bring a roasted, slightly crunchy counterpoint to the soft marshmallows.

• All-purpose flour offers dependable structure; weighing it or spooning it lightly into a cup helps prevent a dry cake.
• Unsweetened cocoa provides concentrated chocolate flavor and absorbs some of the batter’s moisture.
• Evaporated milk gives the icing more body and dairy richness than ordinary milk.
• Sifting the confectioners’ sugar and cocoa is important for a smooth frosting rather than a lumpy one.

Ingredients

• 12 tablespoons unsalted butter, melted and slightly cooled, plus more for the pan
• 1 1/2 cups granulated sugar
• 3 large eggs, at room temperature
• 2 teaspoons vanilla extract
• 1 1/4 cups all-purpose flour, spooned into the measuring cup and leveled
• 1/2 cup unsweetened cocoa powder
• 1 teaspoon baking powder
• 1/2 teaspoon fine salt
• 1 cup pecans, finely chopped
• 4 cups mini marshmallows
• 8 tablespoons unsalted butter, cut into pieces
• 1/3 cup evaporated milk
• 1/3 cup unsweetened cocoa powder
• 3 1/2 cups confectioners’ sugar, sifted
• 1 teaspoon vanilla extract

How to Make This Marshmallow-Topped Chocolate Cake

The main technique is timing. Mix the batter only until the flour disappears, bake the base until just set, and add the marshmallows immediately afterward. Have the frosting ready while the cake is in the oven so it can be poured while the marshmallows are still warm and receptive.

• Spread the batter level so the center and edges finish at roughly the same time.
• Scatter the marshmallows in an even layer rather than piling them in the middle.
• Watch the short second bake closely; the visual cue is puffing and partial fusion, not browning.
• Pour the icing in ribbons and spread it gently instead of pressing down on the marshmallows.

How to Tell When Heavenly Hash Cake Is Done

A successful cake has set edges, a cohesive but moist center, visible pockets of pecan, and a topping that remains recognizably marshmallow-like. The center should not look liquid, but a completely clean toothpick is not necessary for this fudgy style and can indicate that the cake has gone too far.

• Look for a matte surface rather than a glossy, wet center.
• The edges may pull back slightly from the pan while the middle remains softly springy.
• After the second bake, marshmallows should be swollen and shiny, with some outlines still visible.
• The icing should set enough to cut cleanly but remain softer than a hard fudge.

The Variables That Make This 9-by-13 Cake Reliable

The pan is part of the formula: a 9-by-13-inch pan keeps the batter shallow enough for the center to bake before the edges dry. Sugar and butter help retain moisture, while limited mixing keeps the flour from developing a tough gluten network. Carryover heat continues setting the cake after it leaves the oven, so removing it at the moist-crumb stage matters.

• A smaller or deeper pan increases batter depth and usually requires a longer, more cautious bake; begin checking early rather than using the listed time exactly.
• Glass and insulated pans heat differently from dark metal pans, so visual doneness cues are more useful than a rigid time conversion.
• Warm icing flows easily; as it cools, the butter and powdered sugar thicken it into a sliceable coating.
• The marshmallow stage is fast because residual oven heat softens the sugar and gelatin structure quickly.

Common Heavenly Hash Cake Problems and Fixes

Most problems with this cake come from overbaking the base, heating the marshmallows too long, or changing the frosting consistency too abruptly. Measure the flour carefully, use the specified pan when possible, and rely on appearance as well as the timer.

• Dry cake: It was likely overbaked, measured with too much flour, or baked in a pan that was too small. Remove it when moist crumbs remain rather than waiting for a dry toothpick.
• Raw center: The pan may have been too deep, the batter may have been underbaked, or the oven may run cool. Test the center, not just the edge, before adding marshmallows.
• Marshmallows disappear: They were added before the cake was set or left in the oven too long. Add them only after baking and remove the pan as soon as they puff.
• Marshmallows remain firm: Return the cake to the oven for another minute, watching continuously.
• Runny frosting: Whisk in additional sifted confectioners’ sugar a few tablespoons at a time and let it cool briefly before pouring.
• Lumpy or stiff frosting: Sifting prevents lumps; if the frosting is too firm, add evaporated milk by the teaspoon until it flows slowly.

Pecan, Flour and Milk Substitutions

The recipe is most dependable with all-purpose flour, pecans, and evaporated milk, but a few substitutions work well when their effects are understood. The topping combination remains the defining feature even when the nut or dairy choice changes.

• Replace pecans with walnuts in equal measure for a slightly more assertive, less buttery nut flavor.
• Omit the nuts if necessary; the cake will still work, but it will be softer and less characteristic.
• Self-rising flour can replace all-purpose flour only if the added baking powder and salt are omitted or recalculated according to the product’s label.
• Cake flour can make the crumb more delicate, but the cake may be less sturdy beneath the marshmallows.
• Whole milk or light cream can replace evaporated milk in the frosting, though the amount may need adjustment and the icing will be less concentrated.

How to Store, Freeze and Make Heavenly Hash Cake Ahead

Let the cake cool fully before covering it so trapped steam does not make the icing wet. For best texture, serve it after a short rest from the refrigerator, but refrigeration is the cautious choice for extended holding because the frosting contains dairy.

• The cake can be baked and iced a day ahead; cover it tightly and refrigerate if it will be held beyond a short serving window.
• For gatherings, keep the cake chilled during transport and return portions toward room temperature before serving.
• Do not leave the cake at room temperature for more than 2 hours, or more than 1 hour when the temperature is above 90°F (32°C). For additional guidance when serving food at gatherings, consult USDA safe food-handling guidance.
• Freeze individual, well-wrapped squares for up to 1 month. Thaw covered in the refrigerator and avoid reheating, which can liquefy the marshmallow and loosen the icing.

The Southern Tradition Behind Heavenly Hash Cake

There is no single standardized cake formula or firmly established inventor for heavenly hash cake. The name has long been applied to several American desserts, including fruit-and-marshmallow mixtures, ice cream, candy, and baked cakes. This recipe represents the traditional-style Southern sheet-cake interpretation associated with chocolate, marshmallow, and nuts.

• New Orleans Heavenly Hash candy is a related but distinct chocolate-marshmallow-nut confection with a documented regional history.
• Commercial candy versions commonly feature roasted almonds, while Southern cake versions often use pecans or walnuts.
• Calling the recipe Southern-style or traditional-style is more accurate than claiming one universally authentic cake formula.

For regional background on Louisiana Heavenly Hash candy, see the 64 Parishes history of Elmer Candy Company.