Chocolate Sheet Cake

Time1 hour
YieldsServes 12 to 16
Chocolate Sheet Cake
(Mariah Tauger / Los Angeles Times)
For the cake
For the frosting

Heat the oven to 350 degrees. Grease a 9-by-13-by-2½-inch metal baking pan with baking spray.


In a small saucepan, melt the butter and chocolate with 1 cup water over medium heat, stirring occasionally. Remove the pan from the heat and let cool to room temperature.


In a large bowl, whisk together the flour, baking soda and salt. In a medium bowl, whisk together the sugar, sour cream, vanilla and eggs until smooth. Pour the chocolate mixture into the sour cream mixture and stir until smooth. Pour the liquid ingredients over the dry ingredients and stir until just combined. Pour the batter into the prepared pan and smooth the top. Bake until a toothpick inserted in the center of the cake comes out clean, 40 to 45 minutes.


While the cake is in the oven, make the frosting: In a large bowl, whisk together the powdered sugar, cocoa powder and salt. Add the butter and beat with a hand mixer on low speed until evenly combined and clumpy. With the mixer still running, slowly drizzle in the cream and vanilla and beat, starting on low speed and gradually increasing to medium-high, until fluffy and spreadable, 1 to 2 minutes.


Remove the cake from the oven, transfer to a wire rack, and let cool completely. Scrape the frosting onto the cake and use a small offset spatula or table knife to spread it evenly over the top before serving from the pan.

Make Ahead:
The cooled cake can be wrapped in plastic wrap and kept at room temperature for up to 2 days. The frosting can be refrigerated for up to 5 days. Return the frosting to room temperature before beating again and using.