Black Sheet Cake - Add the flour, sugar, cocoa powder, baking powder, baking soda and salt to a large mixing bowl. Combine the soy milk and vinegar in a measuring cup. Web preheat the oven to 350ºf / 175ºc and spray a half sheet pan (13×18 inches) with nonstick cooking spray. Stir then set aside while you prepare the remaining ingredients.
Add the flour, sugar, cocoa powder, baking powder, baking soda and salt to a large mixing bowl. Web preheat the oven to 350ºf / 175ºc and spray a half sheet pan (13×18 inches) with nonstick cooking spray. Combine the soy milk and vinegar in a measuring cup. Stir then set aside while you prepare the remaining ingredients.