• Prep. Preheat the oven to 350℉. Then, lightly grease a 9x13-inch baking dish with nonstick cooking spray.
• Mix dry ingredients and wet ingredients separately. In a large mixing bowl, combine the flour, sugar, cocoa powder, baking soda, and baking powder. Whisk well and set aside. Then, in a medium bowl, whisk together the milk, vegetable oil, vanilla extract, and eggs until thoroughly blended.
  
• Combine them and add water. Pour the wet ingredients into the dry ingredients. Pour the liquid ingredients into the bowl with the dry ingredients. Mix them together gently using a rubber spatula until they are just combined. Slowly pour in the hot water while whisking continuously until the batter becomes smooth and even.
  
• Add cherries. Gently fold in the chopped black cherries until evenly distributed throughout the batter with a spatula.
  
• Bake. Pour the cake batter into the prepared 9x13 baking dish and bake for 30-35 minutes or until a toothpick inserted into the middle of the cake comes out clean. Allow the cake to cool completely in the dish on a wire rack.
  

Assemble.

• Make the frosting. In a large bowl, using a stand mixer or hand mixer, whip the heavy cream until it forms soft peaks. Add the powdered sugar and vanilla extract, continuing to whip until stiff peaks form.
  
• Frost and garnish. Add the whipped cream to the top of the sheet cake and spread evenly. Garnish with shaved chocolate and black cherries. Enjoy!
  
• Serve. Cut into pieces and serve chilled or at room temperature.