Black Velvet Sheet Cake
100% dye-free black velvet cake baked in a 9x13 pan and topped with black cocoa buttercream that's perfectly black without any food coloring! This cake tastes like Oreo cookies, won't turn anyone's mouth black, and is ideal for serving a crowd.
Servings 24 squares
Equipment
Ingredients
Black Velvet Sheet Cake
- 2 Cups (265g) all purpose flour
- 1 2/3 Cups (340g) granulated sugar
- 2/3 Cup (80g) black cocoa powder* see notes
- 2 tsp baking soda
- 1 tsp baking powder
- 1/2 tsp salt
- 1/2 Cup (120ml) vegetable oil
- 2 large eggs, room temperature
- 1 1/2 tsp pure vanilla extract
- 1 Cup (240ml) full-fat buttermilk*, room temperature DIY recipe in notes
- 1 Cup (240ml) hot coffee or hot water
Dye-Free Black Buttercream
- 1 1/2 Cups (339g) unsalted butter, room temperature
- 3 3/4 Cups (450g) powdered sugar
- 3/4 Cup (84g) extra-dark black cocoa powder* Use The Cocoa Trader brand for best results here
- 3 Tbsp whole milk, room temperature
- 2 tsp pure vanilla extract
- 1/4 tsp salt, or to taste
Garnish (optional)
Instructions
Make the Black Velvet Cake
- Preheat the oven to 325ºF (163ºC)and prepare a 9x13 metal baking pan by spraying the sides and bottom with baking spray. Or if you plan on removing the cake from the pan after baking, I recommend spraying the sides with baking spray and lining the bottom of the pan with parchment paper, leaving a slight overhang for easy release.
- Place all of the dry ingredients into the bowl of a stand mixer and stir on low for 30 seconds to fully combine them. Add the vegetable oil, eggs, vanilla, and buttermilk and mix on low until just combined. With the mixer still on low speed, add the hot coffee (or hot water) in a slow stream, then turn the mixer to medium and beat until smooth, about 2 minutes. The batter will be very thin.
- Pour the batter into the prepared baking pan and bake for 30-35 minutes, until a toothpick inserted comes out clean. Cool completely before frosting.
Make the Black Buttercream
- In a stand mixer fitted with a paddle attachment, whip the butter on medium speed until creamy and light in color, about 5 minutes. Scrape down the bowl and paddle, then add half of the powdered sugar. Mix on low speed until just incorporated, then add the rest of the powdered sugar. With the mixer still in the off position, sift in the black cocoa powder and add the vanilla, milk, and salt. Mix on low until all ingredients are thoroughly combined, about 2 minutes, scraping down the bowl and paddle as needed.
- The buttercream will look dark brown at this point, but the color will darken significantly over the next several hours. See the recipe notes for storage instructions if you're not planning on frosting the cake the same day.
Assembly
- Once the black velvet sheet cake is cooled completely, frost with the black buttercream. To create the look pictured, use 2/3 of the black buttercream to frost the cake surface with rustic texture. Add the remaining buttercream into a piping bag fitted with Wilton Tip 4B and pipe a shell border around the edges of the cake. Garnish with googly eye sprinkles.
Notes
*DIY Buttermilk Recipe: add 1 Tbsp of white vinegar to a jar and top it with 1 Cup of whole milk. Stir and let sit for 15 minutes before using in the recipe.
*Black Cocoa Powder: For the darkest black buttercream, use The Cocoa Trader brand (it’s the darkest black cocoa powder out there) BUT this brand is so dark that it will affect the rise of the cake due to its extreme acidity. For this reason, if using The Cocoa Trader brand for the cake layers, use 1/2 cup (60g) of black cocoa powder + 3 Tablespoons (18g) of Dutch-processed cocoa powder. This will ensure the cake rises properly, has a beautiful dark color, and tastes amazing. For any other black cocoa powder brands, you can use the full amount of black cocoa powder called for in the cake recipe BUT the frosting won’t be as black unless you add about 1 tsp of black food color gel.
To Bake as a Layer Cake: use this recipe for Black Velvet Layer Cake.
Make Ahead Tips:
- The Black Velvet Sheet Cake can be made ahead and stored at room temperature, in the pan covered with plastic wrap, for up to 2 days. Alternatively, you can remove the sheet cake from the pan, cover well with plastic wrap, and store in the freezer for up to 2 months before thawing to room temperature.
- The Black Buttercream can be made ahead and stored in an airtight container at room temperature for up to 2 days. Alternatively, you can store it in an airtight container in the refrigerator for up to 2 weeks. When you’re ready to use it, bring it back to room temperature and rewhip with your stand mixer to bring back to frosting consistency.