Lamington-Style Coconut and Chocolate Sheet Cake

By AislePrompt Editorial · Published 2026-05-30 · Updated 2026-05-30

A soft, moist chocolate sheet cake coated in chocolate icing and rolled in shredded coconut, inspired by the iconic Australian lamington dessert. This Australian-inspired recipe, ready in about 60 minutes, layers all-purpose flour, unsweetened cocoa powder, baking powder into a dessert worth slowing down for — great for weekend baking, holiday tables, or any time you want a sweet payoff at the end of a meal. Each serving lands at about 320 calories and feeds 12, so it slots into a weekend bake or a special-occasion dessert tray. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 1 3/4 cups all-purpose flour
• 1/2 cup unsweetened cocoa powder
• 1 1/2 tsp baking powder
• 1 1/2 tsp baking soda
• 1/2 tsp salt
• 3/4 cup unsalted butter, softened
• 2 cups granulated sugar
• 2 large eggs
• 1 tsp vanilla extract
• 1 cup buttermilk
• 1 cup boiling water
• 3 cups powdered sugar
• 1/4 cup unsweetened cocoa powder (for icing)
• 4 tbsp unsalted butter (for icing)
• 1/2 cup milk (for icing)
• 1 tsp vanilla extract (for icing)
• 2 cups shredded sweetened coconut

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Instructions

1. Step 1: Preheat oven to 350°F and grease a 9x13 inch baking pan.
2. Step 2: In a large bowl, sift together 1 3/4 cups all-purpose flour, 1/2 cup unsweetened cocoa powder, 1 1/2 tsp baking powder, 1 1/2 tsp baking soda, and 1/2 tsp salt.
3. Step 3: In a separate bowl, beat 3/4 cup softened unsalted butter with 2 cups granulated sugar until light and fluffy, about 3 minutes.
4. Step 4: Add 2 large eggs one at a time to the butter mixture, beating well after each addition, then stir in 1 tsp vanilla extract.
5. Step 5: Alternately add the dry ingredients and 1 cup buttermilk to the butter mixture, beginning and ending with dry ingredients, mixing until just combined.
6. Step 6: Gradually stir in 1 cup boiling water until the batter is smooth and thin.
7. Step 7: Pour the batter into the prepared pan and bake for 35-40 minutes until a toothpick inserted in the center comes out clean.
8. Step 8: While cake bakes, prepare the icing by combining 3 cups powdered sugar, 1/4 cup cocoa powder, 4 tbsp melted unsalted butter, 1/2 cup milk, and 1 tsp vanilla extract in a saucepan. Heat gently, stirring until smooth and slightly thickened.
9. Step 9: When the cake is cool, cut it into 2-inch squares. Dip each square into the chocolate icing, then roll in 2 cups shredded sweetened coconut until fully coated.
10. Step 10: Place coated lamingtons on a wire rack to set before serving.