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Chocolate Sheet Cake Recipe
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5 from 1 vote

Chocolate Sheet Cake

Easy to make Chocolate Sheet Cake that's moist and has a delicious homemade chocolate frosting that's light and fluffy.
Prep Time15 minutes
Cook Time26 minutes
Cooling Time1 hour
Total Time1 hour 41 minutes
Course: Dessert
Cuisine: American
Servings: 24 pieces
Calories: 368kcal
Author: Julie Evink

Ingredients

Chocolate Sheet Cake

  • 2 ½ cups all-purpose flour* (350 grams)
  • 2 ½ cups granulated sugar (500 grams)
  • ¾ cup unsweetened cocoa powder (75 grams)
  • 2 ½ teaspoons baking soda
  • 1 teaspoon baking powder
  • 1 teaspoon salt
  • 1 ¾ cups buttermilk room temperature
  • 3 large eggs room temperature
  • ½ cup vegetable oil
  • 2 teaspoons vanilla extract
  • 1 cup boiling water

Chocolate Frosting:

  • 5 cups confectioners’ sugar (600 grams)
  • 1 ½ cup unsalted butter (340 grams), slightly melted (if cold from fridge, about 45 seconds in the microwave)
  • ¾ cup unsweetened cocoa powder (75 grams)
  • 4-5 Tablespoons heavy cream 35%
  • 2 teaspoons vanilla extract

Instructions

Chocolate Sheet Cake

  • Preheat oven to 350 degrees Fahrenheit.
  • Line one 18” x 13” sheet cake pan with parchment paper (leave parchment paper slighter higher than the sides of the pan so it’s easier to lift the cake out after). Spray lightly with non-stick cooking spray then set aside.
  • In a large bowl, sift together flour, sugar, unsweetened cocoa powder, baking soda, baking powder and salt. Sift together to remove any lumps (you may need to sift this twice). Set the dry ingredients aside for now.
  • In a separate large bowl, whisk together buttermilk, eggs, vegetable oil and vanilla until well combined.
  • Stir dry ingredients into wet ingredients just until mixed. Do not overmix. Be sure to stir these in by hand – do not use electric beaters for this.
  • Pour the boiling water into the cake batter and stir until well mixed. Use a spatula to scrape down sides and bottom of bowl.
  • Pour cake mix into the prepared sheet cake pan. This will be very full so be careful when transferring it to the oven.
  • Bake in oven for 26 to 27 minutes or until toothpick inserted in middle comes out clean.
  • Remove cake from oven and let cool completely in pan before frosting.

Chocolate Frosting

  • In a large bowl, beat the confectioners’ sugar, butter, cocoa powder, heavy cream and vanilla until light and fluffy (about 5 minutes). If the frosting seems too thick, beat in an additional tablespoon of heavy cream.
  • Smooth an even layer of frosting over the top of the cake and decorate as desired.
  • The cake can remain at room temperature (wrapped well in food-safe plastic wrap) for up to 3 days. After 3 days, refrigerate or freeze the leftovers (wrapped tightly in food-safe plastic wrap then placed into a sealed food safe container). Bring the cake back to room temperature before serving.

Notes

FRIDGE: Store leftover slices of cake in the refrigerator to extend the life of it by a few days.
FREEZER: Freeze an entire chocolate sheet cake or leftover slices in an airtight container, or in a sheet pan wrapped in plastic wrap. Place in the freezer for up to a month. Thaw before eating!

Nutrition

Serving: 1piece | Calories: 368kcal | Carbohydrates: 60g | Protein: 4g | Fat: 14g | Saturated Fat: 9g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 4g | Trans Fat: 0.5g | Cholesterol: 56mg | Sodium: 242mg | Potassium: 151mg | Fiber: 2g | Sugar: 46g | Vitamin A: 450IU | Vitamin C: 0.01mg | Calcium: 45mg | Iron: 1mg