Gluten-Free Dark Chocolate Marshmallow Cake
A decadent layer cake featuring rich dark chocolate cake, topped with toasted marshmallow filling and silky raspberry buttercream, finished with dark chocolate ganache drip and fresh raspberries. The combination of toasted marshmallow sweetness against tart raspberry and deep chocolate creates an elegant dessert with nostalgic appeal. Perfect for special occasions, dinner parties, or celebrations where you want to impress. This version boxed cake mix with homemade buttercream and ganache finishes, making it look and taste bakery-quality despite the convenient starting point.
Ingredients
- 1 box Duncan Hines Dark Chocolate Fudge Cake Mixmilk chocolate or semi-sweet chocolate1:1swapadds dairy
keeps similar texture, lighter flavor
Full guide → - 3 large eggs
- ½ cup butter, melted
- ½ cup strong coffee, room temperature
- ½ cup water
- 16 large marshmallows
- 1 cup powdered sugar
- 1 cup unsalted butter, softened
- ½ teaspoon vanilla extract
- 1 7 ounce jar Marshmallow Fluffhomemade marshmallow paste or whipped marshmallowsimilar volumesubstitute
adds texture and control but requires extra prep
Full guide → - 2 cups unsalted butter, room temperature
- 4 cups powdered sugar
- 2 teaspoon vanilla extract
- 4 tablespoon heavy cream
- 6 tablespoon raspberry pureestrawberry puree or blackberry puree1:1swap
similar acidity and texture, different flavor profile
- 8 ounce dark chocolate, choppedmilk chocolate or semi-sweet chocolate1:1swapadds dairy
keeps similar texture, lighter flavor
Full guide → - 1 cup heavy cream
- 8 whole raspberries, for garnish
Instructions
- 1
Preheat oven to 350F and position rack in middle. Butter two 9-inch round pans, line with parchment, butter parchment, and dust with flour, patting out excess.
- 2
Melt butter in microwave. Combine with cake mix, eggs, coffee, and water in large bowl. Mix on low 1 minute, then medium-high 1 minute.
- 3
Divide batter evenly between pans and bake 25-29 minutes until toothpick inserted in center comes out clean.
- 4
Cool cakes on racks 10 minutes, then invert, remove parchment, and cool completely.
- 5
Switch oven to broil and position rack at lowest level. Line baking sheet with foil and spray with nonstick spray.
- 6
Place marshmallows on sheet and broil watching carefully for 2 minutes until golden and melty. Flip carefully and broil other side 1-2 minutes until brown. Set aside.
- 7
In stand mixer with paddle attachment, beat 1 cup softened butter and 1 cup powdered sugar 1 minute. Add 1/2 teaspoon vanilla and beat 3 minutes on medium-high. Add marshmallow fluff and toasted marshmallows, mix on low 1 minute.
- 8
In clean mixer bowl with paddle, beat 2 cups room-temperature butter and 4 cups powdered sugar on medium-low until sugar incorporates. Add 2 teaspoons vanilla, 4 tablespoons heavy cream, and raspberry puree. Beat on medium 3 minutes until light and fluffy.
- 9
For ganache, combine 1 cup heavy cream and 8 ounces chopped dark chocolate in microwave-safe bowl. Microwave on high 2 minutes, whisk until smooth. Cool 5 minutes until pourable but not hot.
- 10
Place first cake layer on serving surface lined with waxed paper strips. Spread marshmallow filling evenly to edge using offset spatula. Top with second layer.
- 11
Frost top and sides with 2/3 of raspberry buttercream using offset spatula.
- 12
Refrigerate cake while ganache cools. Transfer remaining buttercream to piping bag with large round tip.
- 13
Remove cake from refrigerator and discard waxed paper. Pour ganache over top and use offset to gently push it over sides for dripping effect.
- 14
Refrigerate 5 minutes to set ganache. Pipe buttercream dollops on top and garnish with fresh raspberries.
Tips
Toast marshmallows carefully under broiler - watch constantly as they go from perfect to burnt quickly. Flip only once for even browning.
Keep waxed paper strips under cake while frosting to catch drips, making cleanup easy and presentation clean.
If ganache becomes too stiff before pouring, microwave 5-10 seconds to restore pourable consistency without overheating.
Good to Know
Cover and refrigerate up to 3 days. The ganache keeps the cake moist. Do not freeze as ganache and marshmallow filling texture will degrade upon thawing.
Bake cake layers 1 day ahead and wrap well. Prepare both buttercreams up to 12 hours ahead and refrigerate separately. Assemble and frost on day of serving.
Serve chilled or at room temperature. Slice with a warm, clean knife, wiping between cuts for clean edges. Pairs well with coffee, milk, or champagne.
Common Mistakes
Under-broil marshmallows to avoid them staying too firm and dense; aim for visible browning and slight melting
Overmix raspberry buttercream to avoid breaking; stop when light and fluffy
Rush ganache poured too hot to avoid it running off cake; let cool to proper temperature first
Substitutions
keeps similar texture, lighter flavor
Full guide →similar acidity and texture, different flavor profile
flavor varies slightly by brand
adds texture and control but requires extra prep
Full guide →FAQ
Can I make this without a stand mixer?
Yes, use a handheld electric mixer or whisk by hand. Beating buttercream takes longer manually but yields same result. Ensure butter and ingredients are at stated temperatures for easier incorporation.
What if I don't have fresh raspberries for garnish?
Use frozen raspberries thawed and drained, or skip garnish entirely. The cake is complete without it. You could also use raspberry jam melted as a topper instead of fresh berries.
How long does this cake keep refrigerated?
Covered in refrigerator up to 3 days. The marshmallow and ganache keep it moist throughout storage. Return to room temperature 30 minutes before serving for best flavor and texture.