Name: Viral Cornflake Chocolate Cake
Prep time: 45 min
Cook time: 30 min
Total time: 1 h 15 min
Cuisine: American (Modern)
Ingredients: 1/3 cup (40g) cocoa powder, 100%; 1/2 cup (100g) boiling milk; 1 1/4 cups (160g) all purpose flour; 2/3 cup (140g) granulated sugar; 3 tbsp (46g) sunflower oil; 1 egg; 1 tsp vinegar; 1 tsp baking powder; 1/2 tsp baking soda; 1/2 tsp ground cinnamon (optional); Pinch of salt; 1/2 cup (125g) milk; 1 1/4 cups (225g) dark chocolate (chopped); 2 egg yolks; 1 gelatin sheet, hydrated; 2/3 cup (150g) heavy whipping cream, 35% fat; 1/4 cup (50g) granulated sugar; 1 1/4 cups (200g) dark chocolate (chopped); 2/3 cup (150g) heavy whipping cream; 4 cups (125g) cornflakes

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There is nothing quite as satisfying as a layer cake, but this Viral Cornflake Chocolate Cake takes decadence to a whole new level! It features a moist, tender chocolate cake base, topped with a rich and airy chocolate mousse, and crowned with a surprising, crispy cornflake-chocolate crunch.

The ultimate dessert experience that perfectly balances soft, creamy, and crunchy textures in every single bite.

Recipe Details

Flavor Profile: Deeply chocolatey and satisfying, with a lovely subtle warmth from the cinnamon (if used) in the cake and the dark, luxurious notes of the mousse and topping.
Textures: You get three distinct layers: the tender and moist sponge, the smooth and light melt-in-your-mouth mousse, and the irresistible, crunchy cornflake topping.
Time Commitment: Expect about 45 minutes of active prep time, plus a mandatory minimum chill time of 6 hours in the fridge (or 3 hours in the freezer) for the mousse to set perfectly.
Difficulty: Intermediate. The recipe involves a few distinct stages baking a cake, making a gelatin-set mousse using the bain-marie method for the yolks, and making a quick ganache topping. It’s totally achievable with careful reading!

What You’ll Need

This Viral Cornflake Chocolate Cake is built in three glorious parts. You’ll start with a simple, hot-milk based sponge cake. Next, you’ll prepare a smooth, gelatin-set dark chocolate mousse. Finally, the cake is finished with a simple chocolate ganache mixed with cornflakes for that signature crunchy topping.

Ingredient Notes

Dark Chocolate – Use good quality dark chocolate (around 70% cocoa solids is great) that you enjoy eating, as its flavor will shine through in both the mousse and the topping. Chop it finely for quick and even melting.
Cocoa Powder – Use 100% unsweetened natural cocoa powder for the cake base. Mixing it with boiling milk and sugar is what creates that intense, deep chocolate flavor right from the start.
Gelatin Sheet – This is essential for stabilizing the mousse and giving it that signature light yet firm structure. Be sure to hydrate the sheet fully before stirring it into the warm chocolate mixture.
Heavy Whipping Cream – This should be cold to ensure it whips up properly for the mousse. The 35% fat content provides the best stability and volume for soft peaks.
Vinegar and Baking Soda – These react together to provide leavening power and ensure the cake rises perfectly and stays wonderfully moist.

Add-ins and Substitutions

Here are a few ways you can customize this cornflake chocolate cake to your taste without changing the core method:

Lighter Cake: You can swap the sunflower oil for another neutral oil, like canola or vegetable oil.
Citrus Zest: Add 1/2 teaspoon of finely grated orange zest to the cake batter for a subtle chocolate-orange lift.
Coffee Boost: For an even deeper chocolate flavor (that doesn’t taste like coffee), dissolve 1 teaspoon of instant espresso powder into the boiling milk used for the cake base.
Nutty Crunch: While cornflakes are mandatory for the “viral” texture, you could substitute 1/2 cup of the cornflakes with chopped, toasted nuts (like pecans or hazelnuts) for a different textural element.

Side view of a layered cornflake chocolate cake on a white plate, with a fudgy brownie base, smooth chocolate center, and thick topping of golden cornflakes coated in melted chocolate. — Cornflake Chocolate Cake

How to Make Viral Cornflake Chocolate Cake

Making this triple-layered dessert involves focusing on one component at a time, ensuring each layer is cooled or set before moving to the next.

Step 1: Bake the Chocolate Cake

First, preheat your oven to 180°C (350°F) and line the bottom of your 20 x 6.5 cm (8 x 2.5 in) springform pan.

Boil the milk with the granulated sugar until the sugar is completely dissolved. Mix this warm syrup with the cocoa powder until smooth.
Once the chocolate mixture has cooled slightly, add your wet ingredients the egg, oil, and vinegar and mix well. Crucially, make sure the chocolate mixture is not too hot before adding the egg, or it will cook the egg.
In a separate bowl, whisk together all the dry ingredients: the flour, baking powder, baking soda, salt, and the optional ground cinnamon.
Gently fold the wet and dry mixtures together until just combined.
Pour the batter into the prepared springform pan.
Bake for 25 to 30 minutes, or until a skewer inserted into the center comes out clean. Let the cake cool completely in the pan.

Step 2: Prepare the Chocolate Mousse

This layer is rich yet airy and requires careful cooking to set properly.

Boil the milk, then remove it from the heat and immediately add the chopped dark chocolate. Let it sit for 2 minutes before mixing until smooth. If you still have chunks of chocolate, use the bain-marie method (setting the bowl over a pot of simmering water) to melt it fully.
Mix in the egg yolks and cook the mixture gently over a bain-marie for 1–2 minutes, stirring constantly. This gently cooks the yolks and thickens the base.
Hydrate the gelatin sheet in cold water for two minutes, squeeze out the excess water, and stir it into the warm chocolate mixture until it is fully dissolved.
In a separate bowl, whip the heavy whipping cream with the granulated sugar to soft peaks.
Gently fold the whipped cream into the cooled chocolate mixture until no white streaks remain.
Pour the finished chocolate mousse over the cooled cake base and smooth the top.
Chill in the fridge for 6 hours to overnight, or in the freezer for 3 hours, until the mousse is completely set.

Pro Tip: Do not rush the chilling step for the mousse. The gelatin needs this time to fully set and give the mousse its stable, sliceable texture. An overnight chill in the refrigerator is always best for mousse-based desserts!

Step 3: Finish with Cornflake Topping

The crunchy topping is the perfect contrast to the creamy mousse.

Heat the heavy cream until steaming (do not boil) and pour it over the chopped dark chocolate. Let it sit undisturbed for 2 minutes, then stir until you have a smooth, glossy chocolate ganache.
Mix the finished chocolate ganache with the cornflakes until every piece is coated.
Spread this mixture evenly over the set mousse layer, flattening it slightly with the back of a spoon.
Chill the finished cake for another 10 minutes in the freezer or 20 minutes in the fridge to set the topping before slicing and serving.

Recipe Tips

Avoid Over-mixing: When combining the wet and dry ingredients for the cake, fold them together gently. Over-mixing will develop the flour’s gluten, resulting in a tough, dense cake.
Use a Springform Pan: The springform pan is crucial for easy release of this layered cake, especially with the delicate mousse layer. Run a thin knife around the edge before releasing the spring.
Bain-Marie Control: When cooking the egg yolks into the mousse base, keep the heat low and stir constantly over the bain-marie (a bowl over gently simmering water). This ensures the yolks temper and thicken without scrambling.
Cool Completely: Ensure both the chocolate cake and the mousse base are completely cool/set before adding the next layer. Warm layers will melt or soften the layer beneath, leading to a messy cake.

FAQs

Q: Can I use instant coffee instead of cinnamon in the cake? A: Yes, substituting 1/2 teaspoon of ground cinnamon with 1 teaspoon of instant espresso or coffee powder will deepen the chocolate flavor beautifully without making the cake taste strongly of coffee.

Q: Can I skip the gelatin sheet in the mousse? A: No, the gelatin sheet is necessary to stabilize the mousse. Without it, the mousse will not hold its structure and will remain too soft to slice neatly once chilled.

Q: How long does this Viral Cornflake Chocolate Cake keep? A: The cake will keep well, covered tightly, in the refrigerator for up to 3 to 4 days. The cornflake topping will retain its crunch best in the first two days.

Q: I don’t have a springform pan. What can I use? A: You can use a standard 8-inch round cake pan lined completely with parchment paper, leaving two “wings” of paper hanging over the edges. Once the cake is fully set, use these wings to carefully lift the cake out.

Graphic featuring a round cornflake chocolate cake on a white plate, with a thick brownie-style base, creamy chocolate layer, and crunchy chocolate-covered cornflakes on top, framed by a bold center banner reading “Viral Cornflake Chocolate Cake” in retro cream lettering. — Cornflake Chocolate Cake

Serving Suggestions

This Viral Cornflake Chocolate Cake is rich enough to stand alone, but a few simple additions can make it even better!

A light dusting of cocoa powder just before serving.
A dollop of freshly whipped cream (without sugar) to cut the richness of the dark chocolate.
A side of fresh berries like raspberries or strawberries, whose tartness perfectly balances the sweet chocolate.
A small scoop of vanilla bean ice cream or sorbet.

Make This Recipe in Advance

The best part about this dessert is how well it holds up when made ahead! You can prepare and assemble the entire cake 1 to 2 days in advance, as it needs the extended chilling time anyway.

Cake Base: The chocolate sponge can be baked up to 3 days ahead of time. Wrap it tightly and store it at room temperature.
Mousse: The mousse must be assembled on top of the cake and chilled for at least 6 hours (or overnight) before adding the topping.
Storage: Once fully assembled, store the cake covered in the refrigerator. If you anticipate serving it a few days later, you can delay adding the cornflake topping until a few hours before serving to ensure maximum crispness.

Viral Cornflake Chocolate Cake

Recipe Details