For the Chocolate Cake:
- 1 3/4 cups all-purpose flour
- 3/4 cup unsweetened cocoa powder
- 2 cups granulated sugar
- 1 1/2 teaspoons baking powder
- 1 1/2 teaspoons baking soda
- 1 teaspoon salt
- 2 large eggs
- 1 cup whole milk
- 1/2 cup vegetable oil
- 2 teaspoons vanilla extract
- 1 cup boiling water
For the Blackberry Filling:
- 2 cups fresh blackberries
- 1/2 cup granulated sugar
- 1 tablespoon lemon juice
- 1 tablespoon cornstarch
- 1 tablespoon water
For the Chocolate Frosting:
- 1 cup unsalted butter, softened
- 4 cups powdered sugar
- 1/2 cup unsweetened cocoa powder
- 1/4 cup heavy cream
- 1 teaspoon vanilla extract
- Black decorating gel (for spooky designs)
For Decoration:
- Blackberries (for topping)
- Edible glitter (optional)