Toffee Crunch Sheet Cake Recipe

A buttery sheet cake topped with crunchy toffee bits and a velvety caramel frosting creates an irresistible combination of tender crumb and sweet, nutty crunch.
Difficulty:
Intermediate
Prep Time:
25 mins
Cook Time:
35 mins
Serves:
1 cake (16 slices)
An overhead shot of the Toffee Crunch Sheet Cake reveals its golden-brown surface dotted with glistening toffee pieces and chopped nuts. Soft natural light highlights the silky caramel frosting that drips slightly over the edges. A cross-section view displays the moist, tender crumb interior against the crunchy toffee layer. The cake sits on a vintage white cake stand surrounded by scattered toffee bits and a small bowl of caramel sauce. A slice has been removed, showing the perfect layers and inviting texture, with a fork resting nearby suggesting immediate enjoyment.

Ingredients

<ul class="ingredients-main-list"><li class="ingredients-single-item">For the cake:</li><li class="ingredients-single-item">225g unsalted butter</li><li class="ingredients-single-item">400g granulated sugar</li><li class="ingredients-single-item">4 large eggs, at room temperature</li><li class="ingredients-single-item">2 tsp vanilla extract</li><li class="ingredients-single-item">300g all-purpose flour</li><li class="ingredients-single-item">1 tsp baking powder</li><li class="ingredients-single-item">1/2 tsp baking soda</li><li class="ingredients-single-item">1/2 tsp salt</li><li class="ingredients-single-item">240ml buttermilk (or 230ml milk with 1 tbsp lemon juice)</li><li class="ingredients-single-item">150g toffee bits, divided</li><li class="ingredients-single-item">For the caramel frosting:</li><li class="ingredients-single-item">115g unsalted butter</li><li class="ingredients-single-item">200g light brown sugar, packed</li><li class="ingredients-single-item">80ml heavy cream</li><li class="ingredients-single-item">1/4 tsp salt</li><li class="ingredients-single-item">250g powdered sugar, sifted</li><li class="ingredients-single-item">1 tsp vanilla extract</li><li class="ingredients-single-item">100g chopped pecans or walnuts (optional)</li></ul>

Equipment

<ul class="equipment-main-list"><li class="equipment-single-item">33x23cm (13x9-inch) baking pan</li><li class="equipment-single-item">Stand mixer or electric hand mixer</li><li class="equipment-single-item">Parchment paper</li><li class="equipment-single-item">Medium saucepan</li><li class="equipment-single-item">Offset spatula</li></ul>
BAKE SMARTER

Kitchen Converter

Quickly switch between common baking units without leaving the recipe.

Convert
Result—

Volume uses US cups, tablespoons, and teaspoons. Converting weight to volume depends on the ingredient.

Directions

<ol class="no-list-style"><li class="MethodStepper"><h4 class="step-title">Step 1</h4>Preheat your oven to 180°C (350°F). Line your 33x23cm baking pan with parchment paper, leaving some overhang for easy removal, and lightly grease the exposed sides.</li><li class="MethodStepper"><h4 class="step-title">Step 2</h4>Begin by browning 170g of the butter (save the remaining 55g for later). Place the butter in a light-colored saucepan over medium heat. The butter will melt, foam, and then start to develop golden-brown specks and a nutty aroma. This takes about 5-7 minutes - watch it carefully as it can burn quickly! Once browned, immediately transfer to a large mixing bowl and let cool for 10 minutes. This browning process creates a deep, nutty flavor that elevates the entire cake.</li><li class="MethodStepper"><h4 class="step-title">Step 3</h4>Add the granulated sugar to the browned butter and beat with an electric mixer for 2-3 minutes until well combined. The mixture won't be fluffy like with room-temperature butter, but will have a wet sand-like texture - this is perfect!</li><li class="MethodStepper"><h4 class="step-title">Step 4</h4>Add the eggs one at a time, beating well after each addition. Make sure to scrape down the sides of the bowl to ensure everything is incorporated. Mix in the vanilla extract.</li><li class="MethodStepper"><h4 class="step-title">Step 5</h4>In a separate bowl, whisk together the flour, baking powder, baking soda, and salt. Add the dry ingredients to the butter mixture in three batches, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined after each addition - overbeating will develop gluten and make your cake tough.</li><li class="MethodStepper"><h4 class="step-title">Step 6</h4>Fold in 100g of the toffee bits (reserving 50g for topping), being careful not to overmix. The toffee bits will melt slightly during baking, creating pockets of caramel throughout the cake.</li><li class="MethodStepper"><h4 class="step-title">Step 7</h4>Pour the batter into the prepared pan, spreading it evenly to the corners. Tap the pan gently on the counter a few times to release any air bubbles.</li><li class="MethodStepper"><h4 class="step-title">Step 8</h4>Bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs. The cake should spring back when lightly pressed in the center, and the edges will pull away slightly from the sides of the pan. Allow to cool completely in the pan on a wire rack before frosting.</li><li class="MethodStepper"><h4 class="step-title">Step 9</h4>While the cake is cooling, prepare the caramel frosting. In a medium saucepan, melt the remaining 115g butter over medium heat. Add the brown sugar and stir constantly until the sugar dissolves, about 2 minutes.</li><li class="MethodStepper"><h4 class="step-title">Step 10</h4>Add the heavy cream and salt, then bring the mixture to a gentle boil. Let it bubble for 2 minutes without stirring. Remove from heat and let cool for 15 minutes - this cooling period is crucial for the right frosting consistency.</li><li class="MethodStepper"><h4 class="step-title">Step 11</h4>Transfer the caramel mixture to a mixing bowl and gradually beat in the powdered sugar until smooth and spreadable. Add vanilla extract and mix well. If the frosting seems too thin, add more powdered sugar; if too thick, add a splash of cream.</li><li class="MethodStepper"><h4 class="step-title">Step 12</h4>Working quickly (as the frosting sets fast), spread the warm frosting over the cooled cake using an offset spatula. Immediately sprinkle with the remaining toffee bits and chopped nuts if using. The warmth of the frosting will slightly melt the toffee, creating a beautiful, glossy finish.</li><li class="MethodStepper"><h4 class="step-title">Step 13</h4>Allow the frosting to set for at least 30 minutes before slicing. For clean cuts, dip your knife in hot water and wipe dry between slices. The cake will keep at room temperature, covered, for up to 3 days, though the toffee topping may soften slightly over time.</li></ol>

Nutrition Facts (per serving)

🍽️ Serving Size: 1 slice
🔥 Calories: 385 calories
🥑 Fat: 18 g
🧈 Saturated Fat: 10 g
🍞 Carbohydrates: 52 g
🍭 Sugar: 38 g
🍗 Protein: 4 g
🫀 Cholesterol: 85 mg
🧂 Sodium: 220 mg

Chef’s Notes

A few helpful details for making this recipe.

Why should I brown the butter when making a sheet cake?

Browning butter creates a nutty, complex flavour that elevates the entire cake. The process transforms ordinary butter into a deeply flavourful ingredient as the milk solids caramelise, adding notes of toffee and hazelnut that perfectly complement the sweet caramel frosting.

Can I make this toffee dessert ahead of time for a party?

Yes, you can prepare this cake 1-2 days in advance. Store it in an airtight container at room temperature. The flavours actually develop and improve overnight, though the toffee topping may soften slightly. For the freshest presentation, consider adding the toffee bits just before serving.

What's the best way to achieve a smooth caramel frosting without lumps?

For smooth caramel frosting, ensure your brown sugar dissolves completely in the melted butter, and allow the mixture to cool properly before adding powdered sugar. Sift the powdered sugar beforehand to remove lumps, and add it gradually while beating continuously at a medium speed.

Want to try something else in ...

More recipes you might like

Keep exploring with more recipes from What's Baking.