Easy Moist Chocolate Sheet Cake with Whipped Ganache

This chocolate sheet cake feels right for every occasion, birthdays, potlucks, or simply when you’re craving something rich and chocolatey on the weekend. This one comes together in one bowl, stays moist for days thanks to the oil instead of butter, and gets topped with a light, whipped ganache instead of a heavy buttercream. If you love a good crowd-pleasing dessert, my Peppermint Crisp Tart and Pineapple Fridge Tart are two more favourites worth trying as well.

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Why You’ll Love This Chocolate Sheet Cake

Deeply moist, every time: The vegetable oil keeps this cake soft for days, even straight from the fridge, so there’s no dry slice in sight.

Rich chocolate flavour: Blooming the cocoa powder in boiling water deepens the chocolate taste without making the cake heavy.

Light, not overly sweet, frosting: The whipped ganache is smooth and airy rather than dense, letting the cake itself shine through.

Simple to put together: No layering, no fancy piping, just a straightforward sheet cake that’s easy to bake and easy to frost.

Great for a crowd: This recipe makes 24 pieces, so it’s perfect for gatherings or anytime you need to feed a lot of people with minimal fuss. For more favourites worth sharing, take a look at my Eggless South African Snowballs too.

Ingredients

Chocolate Sheet Cake

Eggs – Give structure to the cake and help trap air when whisked with sugar, creating a lighter crumb while still holding its shape once baked.

White Sugar – Sweetens the cake and helps create a tender texture, contributing to a lighter, more even bake when whisked with the eggs.

Vanilla Essence – Rounds out the chocolate flavour, softening any bitterness from the cocoa and adding warmth to the finished cake.

Vegetable Oil – Keeps the cake moist for days. Unlike butter, oil stays liquid at room temperature, helping the cake stay soft even after refrigeration.

All Purpose Cake Flour – Provides structure, allowing the cake to rise evenly and giving it enough strength to support the ganache without becoming dense.

Baking Powder – Helps the cake rise, creating a gentle lift that keeps the crumb light rather than compact.

Salt – Balances sweetness and sharpens flavour.

Cocoa Powder – Gives the cake its chocolate base. Dissolving it in boiling water before adding it to the batter deepens the flavour and prevents dryness.

Boiling Water – Activates the cocoa powder and helps it blend smoothly into the batter, ensuring a stronger chocolate taste without adding heaviness.

Whipped Ganache

Fresh Cream – Provides richness and structure. When chilled and whipped, it creates a light texture that spreads easily.

Milk Chocolate – Melts smoothly and keeps the ganache soft and approachable.

How to Make a Moist Chocolate Sheet Cake

Step 1: Whisk the eggs and sugar
Whisk the eggs and sugar until light and fluffy. Then add the vanilla essence and vegetable oil, mixing until fully combined.

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Step 2: Fold in the dry ingredients
Fold in the sifted flour, baking powder, and salt, mixing gently to avoid overworking the batter.

Step 3: Bloom the cocoa
Dissolve the cocoa powder in the boiling water. Add the cocoa mixture to the batter and fold gently until smooth.

Step 4: Bake
Pour the batter into a well greased baking tray. Bake at 180°C for about 45 minutes. Start checking after 35 to 40 minutes, as oven temperatures vary. The cake should bake evenly and remain level rather than domed when done.

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Step 5: Make and chill the ganache
Heat the cream in a saucepan over very low heat until hot and steaming, but never boiling. Pour it with the chopped chocolate in a bowl and stir constantly until fully melted and glossy. Cover and refrigerate for 3 to 4 hours, or until thick but still soft.

Step 6: Whip the ganache
Using an electric mixer, whip on medium speed until light, fluffy, and spreadable. Stop as soon as it holds soft peaks. Overwhipping will split the cream.

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Step 7: Frost
Once the cake has cooled and the ganache is whipped, spread it evenly over the cake. Use a spatula to create soft swirls or smooth it neatly for a more polished look. Decorate with chopped chocolate chunks and enjoy!

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Make-Ahead and Storage Tips

Make-ahead: This cake is great for preparing in advance. Bake it a day before serving, then frost with the whipped ganache once it’s fully cooled. For another rich, chocolatey bake, my Simple Moist Chocolate Cake uses a similar method and layers beautifully for a birthday cake.

Freezing: The unfrosted cake freezes well for up to 2 months, wrapped tightly in plastic wrap. I don’t recommend freezing it once the whipped ganache is added, as the texture can turn grainy once thawed.

Storage: Store the frosted cake in an airtight container in the refrigerator for up to 3 days. Let it sit at room temperature for 15 to 20 minutes before serving to soften the ganache.

Frequently Asked Questions

Can I use coffee instead of boiling water? Yes, hot coffee works well in place of boiling water and deepens the chocolate flavour even further without adding a noticeable coffee taste. If you’d like to try it, simply swap the boiling water for the same amount of hot brewed coffee.

Why oil instead of butter? Oil stays liquid at room temperature, which keeps the cake soft and moist for days, even after refrigeration. Butter firms up when cold, which can make a chilled slice feel drier by comparison.

Why did my ganache turn grainy or stiff? This usually happens from overwhipping. Stop as soon as the ganache holds soft peaks and looks like fluffy whipped cream, whipping any longer can cause it to split or firm up like butter.

⭐ Tried this recipe? Leave a star rating and a comment below — I’d love to hear how it turned out! Your feedback helps others find this recipe and bake with confidence.