Preheat your oven to 350°F (175°C). Grease and flour three 8-inch round cake pans.

In a medium bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt. Set aside.

In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Beat in the eggs, one at a time, followed by the vanilla extract.

Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined.

Divide the batter evenly among the prepared cake pans and smooth the tops with a spatula.

Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center of the cakes comes out clean.

Allow the cakes to cool in the pans for 10 minutes before transferring them to a wire rack to cool completely.

In a saucepan, combine the fresh raspberries, granulated sugar, water, and cornstarch.

Cook over medium heat, stirring occasionally, until the raspberries break down and the mixture thickens, about 5-7 minutes.

Remove from heat and let the raspberry filling cool completely before using.

In a large mixing bowl, beat the softened butter until creamy.

Gradually add the powdered sugar and cocoa powder, beating well after each addition.

Add the vanilla extract and 4 tablespoons of heavy cream, and beat until smooth and creamy. If the frosting is too thick, add more heavy cream, one tablespoon at a time, until desired consistency is reached.

Once the cakes are completely cooled, place one layer on a serving plate or cake stand.

Spread a layer of chocolate frosting over the top of the cake layer.

Spoon a layer of raspberry filling over the frosting.

Repeat the process with the remaining cake layers, frosting, and raspberry filling, ending with a layer of frosting on top.

Use a spatula to create a rustic naked look by lightly spreading the frosting around the sides of the cake, leaving some of the cake layers exposed.

Decorate the top of the cake with fresh raspberries, chocolate shavings or curls, and fresh mint leaves for a beautiful finishing touch.