For the Cake:

2 cups all-purpose flour (240 g)

1 1/2 cups granulated sugar (300 g)

3/4 cup unsweetened cocoa powder (75 g)

1 1/2 teaspoons baking powder

1 teaspoon baking soda

1/2 teaspoon salt

3 large eggs

3/4 cup vegetable oil (180 ml)

1 cup buttermilk (240 ml)

2 teaspoons vanilla extract

1/2 cup hot water (120 ml)

For the Blackberry Filling:

1 1/2 cups fresh or frozen blackberries (225 g)

1/4 cup granulated sugar (50 g)

2 tablespoons cornstarch mixed with 2 tablespoons water

1 tablespoon lemon juice

For the Cream Topping:

1 1/2 cups heavy whipping cream (360 ml)

1/4 cup powdered sugar (30 g)

1 teaspoon vanilla extract

Optional Garnishes:

Fresh blackberries, edible flowers, dark chocolate shavings, cocoa powder dusting