Sheet Pan Choco Cake
E
By Emma
Certified Culinary Professional
•
Recipe tested & approved
Half sheet pan chocolate cake with sour cream, coffee, and a glossy cocoa-based frosting. Can spill if pan sides too low. Uses espresso powder for depth. Butter the pan well to avoid sticking. Batter looks runny when coffee’s added but firms up in oven. Frosting melts down sugar and butter with sour cream, then folds in chocolate chips for silkiness. Ideal for large gatherings. Can swap applesauce for oil or oat milk for buttermilk. Watch baking edges, or bake extra cupcakes if unsure. Frost while cake’s warm but not hot for best spread. The recipe balances acidity, bitterness, and sweetness for a rich, tender crumb.
Prep:
20 min
Cook:
22 min
Total:
42 min
Servings:
26 servings
#baking
#chocolate
#sheet cake
#coffee
#sour cream
#frosting
#dessert
#easy baking
Starting with butter, don’t skimp on coating that pan. Cake batter spreading out across a wide surface, it’s fragile—too much and it overflows, too little and it’s gummy. I learned the hard way baking sheet size matters, 2-inch sides help. Sultry, almost syrupy batter after coffee goes in, looks almost too runny but trust it. Smells of rich cocoa and espresso fill air—signals deep flavor building. Watching the edges firm and pull away, that light cracking sound when tapping the pan; all signs to trust your senses over the clock. Frosting melting down with sour cream, sugar granules sizzling then folding into glossy chocolate, pure magic. Letting frosting do its thing on a warm cake means no stubborn spreads; coats effortlessly. This combo of tang and bittersweet notes demands patience but rewards with every bite. The secret? Coffee. Don’t skip it. Adding a bit of apple cider vinegar cuts through richness keeping crumb soft, not heavy. I always keep extra batter for cupcakes if pan looks borderline full. No waste, just bonus treats.
Ingredients
- 2 1/2 cups all purpose flour spooned and leveled
- 1 1/3 cups granulated sugar
- 2/3 cup light brown sugar packed
- 3/4 cup unsweetened cocoa powder sifted
- 2 teaspoons baking powder fresh
- 1 1/4 teaspoons baking soda
- 1 teaspoon espresso powder
- 3/4 teaspoon fine sea salt
- 1 cup sour cream full fat
- 1/3 cup vegetable oil or substitute with melted coconut oil
- 3 large eggs cold from fridge
- 1/2 cup buttermilk or homemade: milk + vinegar
- 1 tablespoon apple cider vinegar
- 1 teaspoon pure vanilla extract
- 1 1/4 cups hot brewed coffee strong and freshly made
- For frosting: 1/3 cup sour cream
- 1/4 cup unsalted butter softened
- 1/2 cup granulated sugar
- 1/3 cup unsweetened cocoa powder sifted
- 1/4 cup bittersweet chocolate chips
- 1 teaspoon vanilla extract
- Pinch fine sea salt
About the ingredients
Measuring flour by spooning into your cup and leveling yields less packed, lighter flour crucial for tender crumb. Cocoa powder needs sifting to avoid clumps and bitterness pockets. Espresso powder is a gamble but raises chocolate intensity without adding actual coffee flavor, voluntary but worth it for nuance. If you don’t have buttermilk, create a quick substitute with regular milk and vinegar or lemon juice; acidity activates baking soda, giving lift very noticeable in thin sheet cakes. Vegetable oil keeps cake moist, but can swap coconut oil for slightly different mouthfeel or avocado oil for neutral flavor. Eggs should be cold for better control of batter structure; warm eggs can cause batter breakdown. Apple cider vinegar adds subtle brightness counteracting sugar and cocoa richness—don’t leave it out. Sourcing unsalted butter fresh is key; old butter is prone to off flavors. Chocolate chips melt smoothly in frosting; avoid cheap waxy chocolates. For the frosting, granulated sugar sizzles when melting but don’t leave on too high heat or you get graininess. Adjust cocoa in frosting for bitterness balance.
Method
- Butter half sheet pan 18x13x2 inches thickly. Scrape butter right into corners and sides so batter won’t creep over; 1 inch sides too shallow, you’ll regret spills. If pan too shallow, grab another or bake cupcakes side by side to use batter fully.
- In large bowl, whisk flour spooned in, sugars, cocoa, baking powder, soda, espresso powder, salt evenly. Sifting cocoa and flour together helps prevent bitter pockets.
- Mix another bowl sour cream, oil, eggs, buttermilk, vinegar, vanilla until silky but don’t overbeat. Eggs cold add lift; warm mix kills air.
- Pour wet into dry. Stir only until barely combined. Lumps okay. Overmix = dense cake. Batter looks thick but accepts hot coffee good.
- Gradually pour in hot coffee. Best to pour slowly while stirring gently. Batter will turn thin and shiny; don’t panic. It’s supposed to be like this; coffee blooms cocoa for deep chocolate. Batter consistency is runny but not watery.
- Pour batter evenly into pan. Use offset spatula or back of spoon to smooth top. Watch that it’s not overflowing.
- Slide into preheated oven at 350°F (adjust oven rack mid-height). Bake 20 to 22 minutes. Start checking at 18. Toothpick inserted should come out with few moist crumbs, not wet batter. Edges pull away when ready. Don’t overbake or cake dries out.
- While cake bakes, start frosting. Melt sour cream, butter, sugar in saucepan on medium-high. Bring to gentle boil, stir frequently so sugar melts evenly. Boil about 25 seconds then remove from heat or risk grainy sugar.
- Immediately whisk in cocoa powder, vanilla, chocolate chips, and salt. Stir vigorously until shiny and glossy. Chips melt into a chocolate ganache-like frosting. If not glossy, heat briefly again but don’t boil twice.
- When cake cools to just warm, pour frosting on top spreading quickly before it stiffens. If frosting sets too fast, warm pan slightly or whisk again. Otherwise frosting will crack when spread.
- Let frosted cake cool fully to let frosting firm up or cut while warm if impatient. Scraping edges is common; that chocolate aroma sets whole kitchen on edge. Decorate with sprinkles or chopped nuts to hide minor cracks and add texture.
- If pan or batter full, don’t force it. Bake a few cupcakes with any leftover batter. These are great for control. Cupcakes usually need 15 minutes at 350; keep an eye on color and springiness.
- Note on substitutions: oil can be swapped for equal melted coconut oil or avocado oil. Buttermilk can be replaced by oat milk plus lemon juice vinegar if lacking. Espresso powder omitted means slightly mellower but less depth. Sour cream in frosting can be replaced with full fat yogurt but texture varies.
- Clean edges of batter on pan before baking; stray crumbs burn and can smoke. Let rest 5 minutes after baking outside oven to settle crumb.
Cooking tips
Start by heavily buttering your sheet pan. Not just the bottom but up the sides—edges trap batter and prevent spilling during baking. Mixing dry ingredients with a whisk aerates and distributes leaveners; no lumps, no uneven rise. When mixing wet ingredients, whisk just until uniform to retain air bubbles. Pour wet into dry gently, stir barely until moistened to avoid gummy cake—lumps here are not your enemy. Incorporating hot coffee last creates a runny batter; do it gradually to avoid over thinning. Spread evenly with an offset spatula or back of spoon; uneven layers bake weirdly, with some parts soggy or dry. Baking time depends on pan and oven. Start checking at 18 minutes. Teeth pick should have moist crumbs, never wet batter. Poke multiple spots—sheet cakes bake unevenly at edges vs center. Frosting step is quick heat on medium-high, watch carefully—just hit a boil then pull off or sugar will recrystallize making gritty frosting. Stirring cocoa and chocolate chips while hot melts chips into glossy shine. Applying frosting while cake warm avoids cracks, sets shiny top. If frosting cools too much, re-warm gently or whip to ease spreading. If pan looks too small, don’t overload; better to bake cupcakes on side than risk overflow and smoke alarms. Those cupcakes bake around 15 minutes, test with toothpick for doneness. The whole process is about timing and cues, not clocks.
Chef's notes
- 💡 Butter pan thick. I mean sides too. Batter creeps over shallow edges always. Grab bigger pan or cupcakes if border close. Scrape crumbs off edges before baking or burnt bits become smoke trouble. Pan size shapes bake time and texture. Too thin? Cake dries, too full? Spill risk. Watch batter flow carefully, offset spatula helps smooth level.
- 💡 Mix dry ingredients well first. Whisk flour, cocoa, soda evenly. Sifting cocoa stops dark bitter clumps. Espresso powder optional but makes chocolate pop without coffee taste. Fresh powder better—stale means dull depth. Add coffee last, hot but pour slow. Batter thins and shines, don’t freak out. Coffee blooms chocolate, adds moist heavy texture not watery thin. Overmix kills air trap, cake dense and flat.
- 💡 Cold eggs key. Warm eggs ruin aeration. Whisk wet ingredients gently, just until uniform; overbeating breaks structure. Sour cream and oils add softness, applesauce can swap oil for less fat but changes mouthfeel. Buttermilk swap with oat milk plus vinegar brightens but less tang. Vinegar essential cuts richness, lifts batter subtly; leave out vinegar, cake heavy and dull.
- 💡 Baking time tricky. Watch edges pull away, slight crackle at touch. Start testing toothpick at 18 minutes. Multiple pokes edges and center. Few moist crumbs is ready, wet batter means wait longer. Overbake drys crumb fast. Cupcakes bake faster, 15 minutes tops, test frequently. Oven rack mid-height balances heat. Cake smells rich cocoa, coffee, slightly toasted butter when near done.
- 💡 Frosting timing crucial. Melt butter, sour cream, sugar slowly on medium-high. Quick boil 20-30 secs max or sugar grinds grainy. Stir constantly. Remove heat first then whisk in cocoa and chips. If frosting thickens too fast apply warm pan or rewhisk to fix spreading. Pour on warm cake not hot or frosting cracks. Chocolate chips melt for silky glossy finish, less chips or no chips means thinner frosting. Store leftovers cold; reheated slightly smooths texture.
Common questions
Can I omit espresso powder?
Yes, flavor less intense. Chocolate tones dull slightly without. Coffee taste not added by espresso powder, just depth. Skip if unavailable but less punch.
What's best substitute for buttermilk?
Oat milk plus vinegar or lemon juice works well. Adds acidity for lift. Yogurt full fat is good in frosting but changes texture. Milk alone lacks acid, cakes flatter, no rise from soda.
Cake edges burned but center raw?
Pan maybe too shallow or oven hot. Position rack middle, use heavier pan with thick sides. Don’t overfill pan, batter level should be low. Cupcakes for extra batter tips avoid spill, adjust bake times. Also test oven temp; many run hot.
How to store cake and keep frosting fresh?
Cool fully first. Wrap tight or airtight container. Refrigerate for a few days or room temp 1 day max; frosting softens more warm. Freeze slices wrapped well. Reheat frosting slightly before serving; whip or warm gently for spreadability.
