Make the Chocolate Cake:

1. Preheat oven to 350°F (175°C). Grease and line three 8-inch round cake pans.
2. In a bowl, whisk flour, cocoa, baking powder, and baking soda.
3. In another bowl, beat eggs, sugar, oil, vanilla, and buttermilk until smooth.
4. Gradually mix dry ingredients into the wet until just combined.
5. Pour batter evenly into pans. Bake for 20–25 minutes or until a toothpick comes out clean.
6. Cool the cakes completely.

Prepare Cherry Filling:

1. In a saucepan, combine cherries, sugar, and cherry juice over medium heat.
2. Dissolve cornstarch in a little cold water, then stir into the pan.
3. Simmer until thickened (3–5 mins). Let cool.

Whip the Cream:

1. Beat chilled heavy cream, powdered sugar, and vanilla until stiff peaks form.

Assemble the Cake:

1. Place the first cake layer on a serving plate. Spread whipped cream, then cherry filling.
2. Repeat with remaining layers.
3. Frost the top and sides with whipped cream.
4. Decorate with chocolate shavings and fresh cherries.