Preheat the oven to 350°F (175°C). Grease the cake pans and line the bottoms with baking parchment.
In a large mixing bowl, combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt. Whisk until well blended.
Add eggs, milk, vegetable oil, and vanilla extract to the dry ingredients. Beat with an electric mixer for 2 minutes until smooth.
Stir in the boiling water until the batter is well combined. The batter will be thin.
Divide the batter evenly between 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, prepare the raspberry filling in a small saucepan over medium heat. Combine raspberries, sugar, cornstarch, and lemon juice. Cook for about 5-7 minutes, stirring gently, until the raspberries break down and the mixture thickens. Remove from heat and let it cool.
For the chocolate ganache, heat the heavy cream in a saucepan until it just begins to simmer. Remove from heat and pour over the chopped chocolate in a bowl. Let it sit for a few minutes, then stir until the chocolate is completely melted and smooth.
Once the cakes are completely cooled, layer the first cake on a serving plate. Spread the raspberry filling evenly over the top.
Place the second cake layer on top and pour the cooled chocolate ganache over the top, allowing it to drip down the sides.
Decorate the cake with additional fresh raspberries and shaved chocolate or a dusting of cocoa powder if desired.
Slice and serve your delicious chocolate raspberry cake. Enjoy!