Chocolate Sheet Cake Recipe

<ul class="ingredients-main-list"><li class="ingredients-single-item">For the cake:</li><li class="ingredients-single-item">250g all-purpose flour</li><li class="ingredients-single-item">400g granulated sugar</li><li class="ingredients-single-item">60g unsweetened cocoa powder</li><li class="ingredients-single-item">2 tsp baking soda</li><li class="ingredients-single-item">1 tsp salt</li><li class="ingredients-single-item">240ml buttermilk (or 240ml milk with 1 tbsp lemon juice)</li><li class="ingredients-single-item">120ml vegetable oil</li><li class="ingredients-single-item">2 large eggs, at room temperature</li><li class="ingredients-single-item">2 tsp vanilla extract</li><li class="ingredients-single-item">240ml hot coffee (or hot water)</li><li class="ingredients-single-item">For the frosting:</li><li class="ingredients-single-item">115g unsalted butter</li><li class="ingredients-single-item">60g unsweetened cocoa powder</li><li class="ingredients-single-item">80ml milk</li><li class="ingredients-single-item">1 tsp vanilla extract</li><li class="ingredients-single-item">375g powdered sugar</li><li class="ingredients-single-item">Pinch of salt</li></ul>

<ul class="equipment-main-list"><li class="equipment-single-item">33x23cm (13x9-inch) baking pan</li><li class="equipment-single-item">Electric mixer (stand or handheld)</li><li class="equipment-single-item">Parchment paper</li><li class="equipment-single-item">Offset spatula</li></ul>

<ol class="no-list-style"><li class="MethodStepper"><h4 class="step-title">Step 1</h4>Preheat your oven to 180°C. Line your 33x23cm baking pan with parchment paper, leaving some overhang for easy removal, and lightly grease any exposed sides. This preparation ensures your cake releases cleanly after baking.</li><li class="MethodStepper"><h4 class="step-title">Step 2</h4>In a large bowl, whisk together the flour, sugar, cocoa powder, baking soda, and salt until thoroughly combined. This uniform distribution of dry ingredients prevents pockets of baking soda or salt in your finished cake.</li><li class="MethodStepper"><h4 class="step-title">Step 3</h4>In a separate medium bowl, whisk the buttermilk, vegetable oil, eggs, and vanilla extract until smooth. The acidity in buttermilk activates the baking soda, creating a tender crumb and helping the cake rise beautifully.</li><li class="MethodStepper"><h4 class="step-title">Step 4</h4>Gradually add the wet ingredients to the dry ingredients, whisking gently until just combined. Be careful not to overmix – this can develop gluten and lead to a tough cake. A few small lumps are perfectly fine!</li><li class="MethodStepper"><h4 class="step-title">Step 5</h4>Slowly pour in the hot coffee (or hot water), stirring gently. The batter will look quite thin – this is exactly right! The hot liquid blooms the cocoa powder, intensifying the chocolate flavor and producing a wonderfully moist texture.</li><li class="MethodStepper"><h4 class="step-title">Step 6</h4>Pour the batter into your prepared pan and tap it gently on the counter a few times to release any air bubbles. This ensures an even rise and smooth top.</li><li class="MethodStepper"><h4 class="step-title">Step 7</h4>Bake for 25-30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs (but no wet batter). Don't overbake – the residual heat will continue cooking the cake as it cools, and slightly underbaking ensures maximum moistness.</li><li class="MethodStepper"><h4 class="step-title">Step 8</h4>While the cake is baking, prepare the frosting. In a medium saucepan over medium heat, melt the butter. Once melted, whisk in the cocoa powder until smooth, then remove from heat. The warm mixture helps dissolve the cocoa completely, preventing any grittiness.</li><li class="MethodStepper"><h4 class="step-title">Step 9</h4>Add the milk and vanilla to the cocoa mixture, whisking until smooth. Then gradually add the powdered sugar and salt, whisking vigorously until the frosting is glossy and pourable but not too runny. If it's too thick, add a splash more milk; if too thin, add a bit more powdered sugar.</li><li class="MethodStepper"><h4 class="step-title">Step 10</h4>When the cake comes out of the oven, let it cool in the pan for about 10 minutes. Then pour the warm frosting over the still-warm cake, spreading it evenly with an offset spatula. Pouring warm frosting over warm cake allows it to slightly penetrate the surface, creating that characteristic fudgy layer between cake and frosting.</li><li class="MethodStepper"><h4 class="step-title">Step 11</h4>Allow the cake to cool completely before cutting into squares and serving. As it cools, the frosting will set to a perfect fudgy consistency. For clean slices, dip your knife in hot water and wipe dry between cuts.</li></ol>