1. Preheat your oven to 350F (180C) and grease and flour two 9-inch round baking pans.
2. In a large mixing bowl, combine flour, sugar, cocoa, baking powder, baking soda, and salt. Add eggs, milk, vegetable oil, and vanilla. Beat on medium speed for 2 minutes.
3. Stir in boiling water until well combined (batter will be thin).
4. Pour batter evenly into the prepared pans.
5. Bake for 30 to 35 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.
6. Once the cakes are completely cooled, place one layer on a serving plate and spread a layer of chocolate frosting over the top.
7. Place the second layer on top and continue to frost the top and sides of the cake.
8. Refrigerate the cake for at least 1 hour before serving.
9. Slice and enjoy
