Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans or line them with parchment paper.

In a large mixing bowl, combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt. Mix well.

Add the eggs, milk, vegetable oil, and vanilla extract to the dry ingredients. Beat with an electric mixer on medium speed for 2 minutes.

Carefully stir in the boiling water until the batter is smooth. The batter will be thin.

Pour the batter evenly into the prepared cake pans. Bake for 30 minutes or until a toothpick inserted in the center comes out clean. Allow the cakes to cool in the pans for 10 minutes, then transfer to a cooling rack to cool completely.

While the cakes are cooling, toss the raspberries with granulated sugar in a small bowl and set aside.

For the frosting, beat the softened butter in a mixing bowl until creamy. Gradually add powdered sugar and cocoa powder, beating until combined. Mix in the vanilla extract and add milk, one tablespoon at a time, until desired consistency is reached.

Once the cakes are completely cool, place one layer on a serving platter. Spread half of the frosting on top, then add the sugared raspberries.

Place the second cake layer on top and frost the top and sides with the remaining chocolate frosting.

Decorate with extra raspberries if desired. Slice and serve.