9x13 Chocolate Cake
This 9x13 chocolate cake is deeply chocolatey, perfectly moist, and topped with a thick layer of chocolate buttercream. Made with both cocoa powder and melted bittersweet chocolate for layered flavor, it is the easiest impressive cake you will ever make.
Servings: 20
Ingredients
Chocolate Cake
- 2 cups (240g) all-purpose flour
- ½ cup (42g) unsweetened natural cocoa powder
- 1¾ cups (346g) granulated sugar
- 2 tsp baking powder
- ½ tsp baking soda
- 1 tsp salt
- ½ cup (100g) vegetable oil
- 3 oz bittersweet chocolate melted and cooled
- 3 large eggs
- 1 cup (227g) buttermilk
- ½ cup (111g) hot strong coffee
- 1 tsp vanilla extract
Chocolate Frosting
- 1 ½ cup (339g) unsalted butter room temperature
- ¾ cup (63g) natural unsweetened cocoa powder
- 3-4 cups (339-454g) powdered sugar
- 1 tsp vanilla extract
- ¼ tsp salt
- 2-4 Tbsp heavy cream
Instructions
Chocolate Cake
- Preheat the oven to 350ºF (180ºC). Grease or line a 9x13 inch baking pan with parchment paper and set aside.
- In a large mixing bowl, whisk together the flour, cocoa powder, granulated sugar, baking powder, baking soda, and salt. Set aside.2 cups (240g) all-purpose flour, ½ cup (42g) unsweetened natural cocoa powder, 1¾ cups (346g) granulated sugar, 2 tsp baking powder, ½ tsp baking soda, 1 tsp salt
- In a separate mixing bowl, whisk together the vegetable oil, melted and cooled bittersweet chocolate, eggs, buttermilk, hot coffee, and vanilla extract until combined.½ cup (100g) vegetable oil, 3 oz bittersweet chocolate, 3 large eggs, 1 cup (227g) buttermilk, ½ cup (111g) hot strong coffee, 1 tsp vanilla extract
- Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.
- Pour the batter into the prepared 9x13 inch pan and spread into an even layer.
- Bake at 350ºF for 30-35 minutes, or until a toothpick inserted in the center comes out clean. Note that dark pans will bake faster than light pans, so start checking at 28 minutes if using a dark pan.
- Allow the cake to cool completely in the pan before frosting.
Chocolate Frosting
- Beat the butter with a hand mixer or stand mixer on medium speed until smooth and creamy, about 2 minutes.1 ½ cup (339g) unsalted butter
- Add the cocoa powder, vanilla, and salt. Mix on low until combined.¾ cup (63g) natural unsweetened cocoa powder, 1 tsp vanilla extract, ¼ tsp salt
- Add 3 cups of powdered sugar one cup at a time, mixing on low after each addition.3-4 cups (339-454g) powdered sugar
- Add 2 tablespoons of heavy cream and mix on medium speed until fluffy, about 1 minute.2-4 Tbsp heavy cream
- Adjust consistency as needed. Add more powdered sugar for a thicker frosting or more milk one tablespoon at a time for a thinner, more spreadable frosting.
- Spread over a completely cooled cake.
Notes
Gluten-Free: Use a 1:1 gluten-free baking flour blend in place of all-purpose flour. I used King Arthur’s Measure for Measure Gluten Free Flour with great results.
To Store: Cover the cake tightly and store at room temperature for up to 3 days. If your kitchen is warm, store in the refrigerator and let slices come to room temperature before serving.
To Make Ahead: Bake the cake one day in advance, cover tightly, and frost the day you plan to serve it.
To Freeze: Freeze the unfrosted cake wrapped tightly in plastic wrap and foil for up to 2 months. Thaw overnight in the refrigerator and frost once fully at room temperature.
Nutrition
Serving: 1g | Calories: 415kcal | Carbohydrates: 51g | Protein: 4g | Fat: 23g | Saturated Fat: 12g | Polyunsaturated Fat: 4g | Monounsaturated Fat: 6g | Trans Fat: 1g | Cholesterol: 68mg | Sodium: 243mg | Potassium: 153mg | Fiber: 3g | Sugar: 37g | Vitamin A: 510IU | Vitamin C: 0.01mg | Calcium: 58mg | Iron: 2mg