Name: Chocolate Mayonnaise Sheet Cake Recipe
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Cuisine: Southern American
Ingredients: 2 cups all-purpose flour; 2/3 cup unsweetened cocoa powder; 1 teaspoon baking soda; 1/2 teaspoon cinnamon; 1/4 teaspoon salt; 1/4 teaspoon baking powder; 3 large eggs; 1 2/3 cups packed light brown sugar; 2 teaspoons vanilla extract; 1 cup mayonnaise; 1 1/3 cups hot water; 1 (8-ounce) package cream cheese, softened; 1/2 cup butter, softened; 2 teaspoons vanilla extract; 1/2 cup unsweetened cocoa powder; 4 1/2 to 5 cups powdered sugar; 2 tablespoons heavy cream

If you’re craving a rich, moist chocolate dessert that’s as easy to make as it is delicious, then you’ve just found your new favorite: the Chocolate Mayonnaise Sheet Cake Recipe. Trust me, this is one of those recipes that sneakily uses mayonnaise to keep the cake incredibly tender and fudgy—your family won’t ever guess the secret ingredient. I absolutely love how this turns out every single time, and I promise you’ll want to make it again and again.

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Why You’ll Love This Recipe

Moist, Tender Texture: The mayonnaise keeps the cake incredibly soft without a hint of greasiness.
Simple Ingredients: You can whip this up with pantry staples you probably already have on hand.
Decadent Chocolate Flavor: Rich cocoa and a luscious cream cheese frosting satisfy every chocolate craving.
Perfect for Any Occasion: From potlucks to weeknight treats, it’s always a crowd-pleaser.

A single square piece of chocolate cake with two layers is shown on a white plate. The bottom layer is dark brown, moist, and crumbly with small air pockets, while the top layer is thick, smooth, and light brown chocolate frosting with swirled textured peaks. In the background, there is a yellow-lidded, mostly white jar of mayonnaise and a pan of more chocolate cake blurred out. The scene is set on a white marbled surface. Photo taken with an iphone --ar 2:3 --v 7 - Chocolate Mayonnaise Sheet Cake, moist chocolate cake with mayonnaise, easy chocolate sheet cake, fudgy chocolate cake recipe, quick homemade chocolate cake

Ingredients You’ll Need

The magic of this Chocolate Mayonnaise Sheet Cake Recipe comes from the balance between classic baking ingredients and that surprising mayo addition which brings the cake to a whole new level of moistness. When shopping, aim for good-quality cocoa powder and fresh eggs—they really make a difference.

Flat lay of a small mound of all-purpose flour, a small white ceramic bowl filled with unsweetened cocoa powder, a small white bowl with cinnamon powder, a few whole light brown eggs with clean shells, a small pile of light brown sugar crystals, a small white bowl of creamy mayonnaise, a small white bowl of hot water steaming slightly, a block of soft cream cheese next to a slab of softened butter on a white plate, a small white bowl containing powdered sugar, and a small white bowl with heavy cream, all arranged in perfect symmetry on a clean white marble surface, soft natural light, photo taken with an iPhone, professional food photography style, fresh ingredients, white ceramic bowls, no bottles, no duplicates, no utensils, no packaging --ar 2:3 --v 7 --p m7354615311229779997 - Chocolate Mayonnaise Sheet Cake, moist chocolate cake with mayonnaise, easy chocolate sheet cake, fudgy chocolate cake recipe, quick homemade chocolate cake

All-purpose flour: Provides structure; make sure to spoon and level for accuracy.
Unsweetened cocoa powder: Choose a Dutch-processed cocoa if you want a milder, chocolatey taste.
Baking soda: Helps the cake rise and adds to the tender crumb.
Cinnamon: Just a touch for warmth and complexity in the chocolate flavor.
Salt: Enhances sweetness and balances flavors.
Baking powder: Works alongside baking soda for perfect rise.
Eggs: Bind everything together, bring structure, and add richness.
Light brown sugar: Adds moisture and subtle caramel notes.
Vanilla extract: Elevates the overall flavor beautifully.
Mayonnaise: The secret ingredient that keeps the cake moist—use a good quality brand with simple ingredients for best results.
Hot water: Helps dissolve cocoa and activates leavening.
Cream cheese (softened): For that creamy, tangy frosting that pairs perfectly with the chocolate.
Butter (softened): Adds richness and smoothness to the frosting.
Powdered sugar: Sweetens and thickens the frosting.
Heavy cream: Lightens the frosting and helps get that perfect spreadable consistency.

Note: You’ll find the complete list of ingredients, along with their exact measurements, in the printable recipe card at the bottom of this post.

Variations

One of the things I love about this Chocolate Mayonnaise Sheet Cake Recipe is how forgiving it is to play around with. Whether you want to tweak it for a dietary preference or just add a little flair, there’s plenty of room for creativity.

Gluten-Free Version: I’ve had great luck swapping in a gluten-free all-purpose flour blend 1:1; just check your cocoa and baking powder labels to keep it truly gluten-free.
Spice It Up: Adding a pinch of cayenne pepper or espresso powder amps up the chocolate flavor and adds a fun surprise.
Frosting Swaps: Sometimes I swap the cream cheese frosting for a simple chocolate ganache for an extra rich finish.
Mini Cakes: Try making cupcake-sized versions for parties—they bake faster and make perfect individual treats.

How to Make Chocolate Mayonnaise Sheet Cake Recipe

Step 1: Prepping the Dry Ingredients

Start by preheating your oven to 350°F and grease a 9×13-inch pan with baking spray that includes flour (this helps prevent sticking better than butter alone). In a medium bowl, whisk together the flour, cocoa powder, baking soda, cinnamon, salt, and baking powder. This combo is what gives the cake that perfect rise and deep flavor—mixing it well now ensures it’s evenly distributed throughout the batter.

Step 2: Mixing the Wet Ingredients

Using an electric mixer, beat the eggs, brown sugar, and vanilla at medium-high speed for about 3 minutes until light and fluffy. This step is key because it builds air into the batter, making it lighter so your cake isn’t dense. Then, switch the mixer to low and add in the mayonnaise, beating just until everything is combined—don’t overdo it here, or you’ll lose that lovely fluffiness you just whipped in.

Step 3: Combining Dry and Wet Ingredients

Next, you’re going to alternate adding the flour mixture and hot water to the wet ingredients. Add the flour in three parts and the hot water in two, beating just until the ingredients are incorporated before adding the next addition. This alternating method helps the batter develop properly and contributes to the cake’s moist crumb. The hot water melts the cocoa powders and activates the leavening agents for that perfect rise.

Step 4: Bake and Cool

Pour the batter into your prepared pan and smooth the top with a spatula. Bake for 30 to 35 minutes—start checking at 30 minutes by inserting a toothpick; it should come out with just a few moist crumbs attached. After baking, be patient and let the cake cool completely before adding the frosting. This step is crucial to avoid melty frosting or a soggy cake top.

Step 5: Cream Cheese Frosting

Beat together the softened cream cheese, butter, and vanilla with an electric mixer until creamy and smooth. In a separate bowl, whisk together the cocoa powder and powdered sugar. Gradually beat half the cocoa-sugar mixture into the cream cheese blend, then mix in the heavy cream. Finish by mixing in the remaining powdered sugar mixture until the frosting is fluffy but spreadable—if it feels too thick, add a bit more cream, a teaspoon at a time. Spread the frosting evenly over the cooled cake for that perfect sweet finish.

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Pro Tips for Making Chocolate Mayonnaise Sheet Cake Recipe

Warm Ingredients Work Wonders: Using room temperature eggs, butter, and cream cheese makes mixing smoother and prevents lumps.
Don’t Overmix the Batter: Once you start adding flour and water, mix until just combined to keep the cake tender, not tough.
Check Baking Time Early: Ovens vary wildly; check your cake at 30 minutes to avoid overbaking and drying out.
Cool Completely Before Frosting: I learned this the hard way—frosting melts and slides off hot cake, so patience pays off!

How to Serve Chocolate Mayonnaise Sheet Cake Recipe

A single thick slice of dark brown chocolate cake sits on a simple white plate, showing a soft, moist texture with a few small crumbs around the base. The cake is topped with one thick, smooth layer of rich milk chocolate frosting that has visible swirls and peaks, giving it a creamy and fluffy look. The background is a white marbled texture, and part of a blurred chocolate ingredient box is visible behind the cake. Photo taken with an iphone --ar 2:3 --v 7 - Chocolate Mayonnaise Sheet Cake, moist chocolate cake with mayonnaise, easy chocolate sheet cake, fudgy chocolate cake recipe, quick homemade chocolate cake

Garnishes

For garnishing, I adore a simple dusting of cocoa powder on top or a sprinkle of mini chocolate chips for extra texture. Sometimes a few fresh raspberries or a sprig of mint adds a lovely pop of color, especially if you’re serving this at a party. You can also toast some chopped nuts like pecans or walnuts to sprinkle on top for a crunchy contrast.

Side Dishes

Though this cake is a showstopper on its own, I’ve enjoyed pairing it with a scoop of vanilla ice cream or a dollop of freshly whipped cream. Simple sides like fresh berries or a bright citrus salad balance the richness beautifully and give the meal a fresh finish.

Creative Ways to Present

For special occasions, I’ve laid this cake out in individual squares topped with edible flowers or delicate chocolate shavings. Turning it into little layered parfaits by crumbling cake pieces between layers of mousse or whipped cream is another fun way I’ve surprised guests. It’s a versatile cake that looks just as good as it tastes!

Make Ahead and Storage

Storing Leftovers

I store leftover Chocolate Mayonnaise Sheet Cake in an airtight container in the refrigerator. It keeps beautifully for up to 4 days, and honestly, the flavors meld together even more, making it taste just as incredible the next day.

Freezing

If you want to freeze the cake, I recommend freezing it unfrosted first, tightly wrapped in plastic wrap and aluminum foil. When ready to serve, thaw overnight in the fridge and frost it fresh—this keeps the frosting nice and fluffy rather than dense or watery.

Reheating

Since this is a moist sheet cake, I usually enjoy it cold or at room temperature, but if you prefer it warm, gently microwave individual slices for 10-15 seconds. Be careful not to overheat, or the frosting might melt away.

FAQs

Why do you use mayonnaise in this Chocolate Mayonnaise Sheet Cake Recipe?

Mayonnaise might sound unusual in a cake, but it’s essentially oil and eggs combined, which keeps the cake moist and tender without adding any tangy flavor. It acts as a secret ingredient that makes this cake incredibly soft and delicious every time.
Can I substitute mayo with something else?

If you don’t have mayonnaise, you can try using plain yogurt or sour cream as a substitute. However, these can alter the flavor slightly and might need recipe adjustments. Mayonnaise is the best option for maintaining the cake’s iconic moist texture.
How do I know when the cake is done baking?

Insert a toothpick into the center of the cake at around 30 minutes of baking. If it comes out with just a few moist crumbs (not wet batter), the cake is done. Be careful not to overbake, as it dries the cake out.
Can I make this cake gluten-free?

Yes! Using a gluten-free all-purpose flour blend that matches 1:1 the amount of regular flour works well. Just double-check all your other ingredients are gluten-free, especially baking powder and cocoa powder.

Final Thoughts

This Chocolate Mayonnaise Sheet Cake Recipe holds a special place in my heart—it’s that perfect mix of old-fashioned comfort and modern ease that never fails to impress. Whenever I bring it out at family gatherings, it disappears fast, and I get so many questions about what makes it so moist and delicious. I encourage you to try this recipe, whether you’re a seasoned baker or just starting out, because it’s genuinely that good and surprisingly simple. Plus, it’s a great way to surprise your loved ones with a slice of cake that’s out of the ordinary (in the best way).