Preheat your oven to 350°F (175°C). Grease and flour the two round cake pans.
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. Mix on medium speed until well combined.
Gradually stir in the boiling water until the batter is smooth (the batter will be thin).
Divide the batter evenly between the two prepared cake pans. Bake for 30 minutes, or until a toothpick inserted into the center comes out clean. Let the cakes 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 saucepan over medium heat, combine the raspberries, sugar, cornstarch, and lemon juice. Cook the mixture, stirring gently until it thickens (about 5-7 minutes). Remove from heat and let cool.
For the chocolate ganache, heat the heavy cream in a saucepan over medium heat until it just begins to simmer. Remove from heat and add the chopped chocolate. Let it sit for 2-3 minutes, then stir until smooth. Allow it to cool slightly.
Once the cakes are completely cooled, place one layer on a serving plate. Spread the raspberry filling over the top. Place the second layer on top and pour the chocolate ganache over the entire cake, allowing it to drip down the sides.
Allow the ganache to set for at least 30 minutes before slicing.