Southern Coca-Cola Cake with Fudgy Marshmallow Frosting 🥤🍫

Print Recipe Jump to Recipe

Hi, I’m Raya, welcome back to my kitchen! 👋 Today I’m sharing a dessert that makes people say “wait, there is soda in that cake?” with my Southern Coca Cola cake. It is a moist chocolate sheet cake made with cola and buttermilk, studded with tiny marshmallows, and covered in a warm, fudgy frosting that sets into a thin, glossy shell. This cake has been a potluck favorite across the South for decades, and one bite will tell you why. It comes together in one saucepan and one pan, so it is perfect for busy days. Grab your whisk, and let us bake this nostalgic favorite together!

Why You’ll Love This Recipe 💕

• Ultra-Moist Crumb: Cola and buttermilk make the cake soft, tender, and almost fudgy.
• Gooey Marshmallow Surprise: The mini marshmallows melt into the batter and add a sweet, chewy texture.
• Warm Fudgy Frosting: The frosting is poured over the hot cake, so it soaks in slightly and sets into a glossy fudge layer.
• One-Pan Simplicity: A 9×13 pan and one saucepan are all you need, which makes cleanup easy.
• Perfect for a Crowd: It slices into 15 generous squares, so it is ideal for potlucks and parties.

Key Ingredients for Coca Cola Cake 🛒

For the Chocolate Cola Cake

• All-Purpose Flour (2 cups / 250g): The base of the cake.
• Granulated Sugar (2 cups / 400g): Sweetens and keeps the cake moist.
• Fine Sea Salt (1/2 tsp): Balances the sweetness.
• Unsalted Butter (1 cup / 225g): Melted with the cola and cocoa for a rich, fudgy base.
• Unsweetened Cocoa Powder (1/4 cup / 25g): For deep chocolate flavor.
• Full-Sugar Cola (1 cup / 240ml): Adds sweetness and a subtle caramel flavor. Do not use diet soda.
• Buttermilk (1/2 cup / 120ml, room temperature): Makes the crumb tender.
• Large Eggs (2, room temperature): Add structure.
• Baking Soda (1 tsp) and Vanilla Extract (1 tsp): For lift and flavor.
• Mini Marshmallows (1 1/2 cups / 75g): Folded into the batter.

For the Fudgy Cola Frosting

• Unsalted Butter (1/2 cup / 115g): Makes the frosting rich and smooth.
• Unsweetened Cocoa Powder (3 tbsp / 20g): For chocolate flavor.
• Full-Sugar Cola (6 tbsp / 90ml): Gives a signature flavor.
• Powdered Sugar (3 3/4 cups / 450g, sifted): Sweetens and thickens.
• Vanilla Extract (1 tsp): For balance.
• Chopped Pecans (1 cup / 115g, optional) and Extra Mini Marshmallows (1/2 cup, optional): For crunch and a pretty finish.

Baker’s Note: The batter is very thin, and that is exactly right. It bakes into a super moist cake! Do not worry if the marshmallows float to the top, because they melt into the cake and form a lovely sweet crust. If you love chocolate sheet cakes, check out my Texas Sheet Cake and my Chocolate Overload Drip Cake.

Step-by-Step Instructions 👩‍🍳

Step 1: Prepare the Pan and Oven

Preheat your oven to 350°F (175°C). Grease a 9×13-inch (23×33 cm) baking pan and line it with parchment paper.

Step 2: Mix the Dry Ingredients

In a large bowl, whisk the flour, sugar, and salt until combined.

Step 3: Boil the Butter, Cocoa, and Cola

In a medium saucepan, combine the butter, cocoa, and 1 cup of cola. Bring to a gentle boil over medium heat, whisking until smooth. Pour the hot mixture over the dry ingredients and stir until combined.

Step 4: Finish the Batter and Bake

Whisk the buttermilk, eggs, baking soda, and vanilla together, then stir them into the batter. Fold in the mini marshmallows and pour the batter into the prepared pan. Bake for 30 to 35 minutes, until a toothpick comes out with a few moist crumbs.

Step 5: Make the Frosting

While the cake bakes, combine the butter, cocoa, and 6 tablespoons of cola in a saucepan. Bring to a boil, then remove from the heat. Whisk in the powdered sugar and vanilla until smooth and glossy. Stir in the pecans if using.

Step 6: Frost the Warm Cake

Pour the warm frosting over the hot cake as soon as it comes out of the oven and spread it evenly. Press a few extra mini marshmallows into the frosting if you like. Let the cake cool for at least 30 minutes so the frosting can set.

Baker’s Tips for Success 💡

• Use Full-Sugar Cola: Diet soda does not give the same flavor or moisture.
• Frost While the Cake Is Hot: The warm frosting sinks in slightly and sets into a thin, fudgy glaze.
• Sift the Powdered Sugar: This stops lumps and gives the frosting a glossy finish.
• Do Not Overbake: Pull the cake out as soon as a toothpick shows a few moist crumbs for a soft, fudgy texture.
• Cut with a Sharp Knife: Wipe it between cuts for clean, neat squares.

Curious about the soda behind the cake? 🥤 Read the story of Coca-Cola and how this famous soda became a Southern kitchen staple.

How to Serve Coca Cola Cake 🍽️

Serve the cake warm or at room temperature, cut into squares. A scoop of vanilla ice cream melting over a warm square is pure heaven.

How to Store Coca Cola Cake 🧊

• At Room Temperature: Keep the cake covered for up to 4 days.
• In the Refrigerator: Store it in an airtight container for up to 1 week. Bring squares to room temperature before serving.
• In the Freezer: Wrap individual squares tightly and freeze for up to 3 months. Thaw on the counter for 30 minutes.

Frequently Asked Questions ❓

Can I use diet cola or another soda?

Full-sugar cola gives the best flavor and texture. Other colas work, but diet soda can make the cake less moist and the flavor less rich.

What is the difference between Coca Cola cake and Texas sheet cake?

The two cakes are similar, but Coca Cola cake uses cola and mini marshmallows, while Texas sheet cake relies on a buttery, thinner base and a pecan-topped frosting.

Why did my marshmallows disappear?

They melt into the batter while baking and add moisture and sweetness. If you want visible marshmallows, press a few extra into the warm frosting.

Can I make Coca Cola cake ahead of time?

Yes. It tastes even better the next day, because the frosting settles into the cake. Keep it covered at room temperature overnight.