Recipe

Fudgy Chocolate Sheet Cake

A classic one-pan chocolate cake with a tender, moist crumb and a warm cocoa frosting you pour on while it is hot for that signature glossy finish.

By Matt Campbell

•

4.8

A freshly frosted chocolate sheet cake in a rectangular metal pan on a light kitchen counter, glossy cocoa frosting set with a few clean slices cut out

Jump to Recipe

If you want a dessert that feeds a crowd, forgives a slightly chaotic kitchen, and still tastes like you absolutely had your life together, this chocolate sheet cake is the move. It bakes in one pan, stays ridiculously moist, and the frosting is the best kind of dramatic: you pour it on warm and it turns glossy, fudgy, and sliceable like it was born to be taken to a potluck.

This is that old-school, no-frills chocolate cake energy, but with a couple smart upgrades that keep it plush, not dry. We're using sour cream for tenderness, blooming the cocoa with hot coffee (or water) for deeper flavor, and finishing with a frosting that melts into the top just enough to become one with the cake. No layers. No piping bags. Just big chocolate payoff.

Measured flour, sugar, cocoa powder, eggs, butter, sour cream, and vanilla arranged on a bright kitchen counter with a 9x13 pan nearby

Why It Works

Big chocolate flavor without fancy chocolate: Blooming cocoa in hot liquid wakes it up and makes the cake taste deeper and more chocolatey.
Moist, tender crumb: Sour cream brings richness and keeps the cake soft for days.
One-pan simplicity: No leveling, stacking, or stressing. Bake, frost, slice, win.
That signature pour-on frosting: Putting warm frosting on a warm cake gives you a glossy top that sets into a fudgy layer.

A hand pouring warm cocoa frosting from a saucepan over a baked chocolate sheet cake in a rectangular pan on a kitchen counter

Pairs Well With

Storage Tips

Room temperature: Cover the pan tightly with foil or a lid and keep it on the counter for up to 2 days. If your kitchen runs warm, move it to the fridge sooner.

Refrigerator: Store covered for up to 5 days. For the best texture, let slices sit at room temp for 20 to 30 minutes before eating.

Freezer: Freeze individual slices on a sheet pan until firm, then wrap in plastic and stash in a freezer bag for up to 2 months. Thaw overnight in the fridge or for a couple hours at room temp.

Chocolate sheet cake slices stacked in a clear airtight container on a kitchen counter, frosting layer visible

Common Questions

What size pan should I use for sheet cake?

This recipe is written for a 9x13-inch pan, which is the most common “home sheet cake” size. If you use a larger pan like a 10x15 jelly roll pan, the cake will bake thinner and faster and you may want to scale the recipe up.

Can I make this in a jelly roll pan (10x15)?

Yes, but the thickness will change. For a true cafeteria-style sheet cake in a 10x15 pan, increase the batter by about 50% and start checking for doneness a few minutes earlier than you think.

Why is my sheet cake dry?

Usually it is overbaking or overmeasuring flour. Use the spoon-and-level method for flour, and start checking at the early end of the bake window. You want a few moist crumbs on the toothpick, not a clean, dusty one.

Can I swap sour cream for yogurt?

Yep. Use full-fat plain Greek yogurt 1:1. The cake will still be tender and moist.

Do I frost the cake hot or cool?

Let the cake cool for about 10 minutes, then pour the warm frosting on. Warm-on-warm is the whole magic trick here.

Can I make it ahead?

Absolutely. Bake and frost the day before, cover tightly, and keep it at cool room temperature or in the fridge. It slices even cleaner the next day.

Matt Campbell

I have always had a huge passion for the culinary arts, people, working as a team, and so on. I wanted to pursue my love for cooking initially at Virginia Commonwealth University with a culinary arts degree; however, I instead decided to apply myself and acquire more practical skills. My end goal is to eventually open my own restaurant or similar establishment.

Kitchen Essentials

9x13-inch baking pan
Mixing bowls (1 large, 1 medium)
Whisk and rubber spatula
Measuring cups and spoons
Small saucepan (for frosting)
Offset spatula or spoon (to spread frosting)
Cooling rack (helpful, not required)

I love a dessert that doesn't ask me to perform. Sheet cake is that friend who shows up in sweatpants, brings good vibes, and still somehow looks great in photos. The first time I nailed the pour-on frosting thing, I just stood there for a second watching it spread like chocolate lava and thought, okay, this is why people bake. Now it's my go-to for birthdays, cookouts, and those random Tuesdays when you want something cozy and chocolatey but don't want to wash six cake pans afterward.