A fluffy, light, tender cake thats indulgent with a velvety fudge buttercream frosting.

It was later popularized by the mayonnaise company Best Foods to get to promote their product.

What Does Mayonnaise Add to Cakes?

Slice of Chocolate Mayonnaise Sheet Cake on a Plate with a Fork

Simply Recipes / Annika Panikker

Mayonnaise is made up of eggs, oil, and acid.

When we add it to the batter, it ensures a very soft and fluffy cake.

Flavor-wise, you dont taste the mayonnaise in the baked cake.

Chocolate Mayonnaise Sheet Cake in a Baking Pan, Surrounded by Small Plates, Utensils, and One Small Plate with a Slice of Cake

Simply Recipes / Annika Panikker

Ideally, use a full-fat mayonnaise for the best results.

I wouldnt recommend using vegan mayonnaise in this recipe.

You could use any unsweetened cocoa powder you have on hand.

Baking Pan of Chocolate Mayonnaise Sheet Cake with Slices Cut

Simply Recipes / Annika Panikker

I prefer Dutch processed as it is darker with a richness that feels more indulgent.

To Frost or Not To Frost?

It is silky smooth and creamy which makes every bite scrumptious.

Dry Ingredients (All-Purpose Flour, Dutch Processed Cocoa Powder, etc) Mixed Together in a Bowl Using a Spatula for Chocolate Mayonnaise Sheet Cake Recipe

Simply Recipes / Annika Panikker

Hence my recommendation is to frost.

In a glass measuring cup, add the instant coffee to the hot water.

Mix until dissolved and set aside.

Espresso Powder Mixed with Hot Water in a Pyrex Cup for Chocolate Sheet Cake Recipe

Simply Recipes / Annika Panikker

Add the eggs one at a time and beat well.

double-check to scrape down the sides of the bowl with a spatula periodically to ensure everything is getting incorporated.

Pour in the vanilla and beat to mix.

Wet Ingredients Mixed Together in a Bowl for Chocolate Mayonnaise Sheet Cake Recipe

Simply Recipes / Annika Panikker

Add the second part of the dry ingredients with the other half of the hot coffee and beat well.

Add the final third of the dry ingredients and give it a good mix.

The batter should be neither stiff nor runny.

Wet and Dry Ingredients Slowly Mixed Together in a Bowl for Sheet Cake Recipe

Simply Recipes / Annika Panikker

Let the cake cool completely before frosting.

(It should take 40 to 70 seconds total).

Set the chocolate aside to cool.

Chocolate Mayonnaise Sheet Cake Batter in a Bowl

Simply Recipes / Annika Panikker

In a large bowl, use an electric mixer to beat the butter until its creamy and fluffy.

Add the powdered sugar to the creamed butter.

Starting on the lowest speed, beat the mixture together.

Chocolate Mayonnaise Sheet Cake Batter Poured into a Baking Pan

Simply Recipes / Annika Panikker

Add the cocoa powder to the frosting and beat well until combined.

confirm to scrape down the sides every now and then for a smooth frosting.

Add the cream and melted dark chocolate to the frosting and beat well until combined.

Chocolate Mayonnaise Sheet Cake Batter in a 9x13 Baking Pan

Simply Recipes / Annika Panikker

Let this set in the fridge for 10 minutes before frosting the cake.

Tip

ensure the melted chocolate has had a chance to cool slightly.

Slice and serve the cake.

Baked Chocolate Mayonnaise Sheet Cake in a Baking Pan

Simply Recipes / Annika Panikker

Once the cake is baked, leave it in the baking tin and cover it with plastic wrap.

Leave it at room temperature for 1 day or refrigerate for up to 7 days.

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Clean Toothpick after Inserted into Chocolate Mayonnaise Sheet Cake

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Bowl of Melted Chocolate for Chocolate Sheet Cake Recipe

Simply Recipes / Annika Panikker

Whipped Butter in a Bowl

Simply Recipes / Annika Panikker

Sugar Whipped with Butter in a Bowl for Chocolate Mayonnaise Sheet Cake

Simply Recipes / Annika Panikker

Chocolate Powder Mixed into Buttered Sugar and Butter for Chocolate Mayonnaise Sheet Cake Recipe

Simply Recipes / Annika Panikker

Heavy Cream Added to the Bowl with the Chocolate Butter Mixture

Simply Recipes / Annika Panikker

Bowl of Chocolate Buttercream for Sheet Cake Recipe

Simply Recipes / Annika Panikker

Chocolate Buttercream Spooned onto Sheet Cake in the Baking Pan

Back of a Spoon Used to Make Wispy Shapes on the Icing for Chocolate Mayonnaise Sheet Cake

Simply Recipes / Annika Panikker

Chocolate Mayonnaise Sheet Cake

Simply Recipes / Annika Panikker