Preheat oven to 360F / 180C Two 9-inch baking pans should be floured. Set aside. Mix flour, sugar, cocoa, and baking soda in a large bowl with a stand mixer.
Add the eggs, vegetable oil, vanilla extract, and milk. Blend for 3 minutes. Add boiling water to the bowl. To stir, you can use a rubber spatula. The batter will be very thick.
Divide the batter equally between two pans. After this, Bake on the middle rack for 30-35 minutes or until a toothpick inserted into the center comes out clean and leaves only crumbs. Allow it to cool for 10 minutes before removing the pans. Let cool completely.
Prepare a chocolate buttercream frosting in the meantime. You can beat the butter with a stand mixer until it becomes fluffy. Add in the cocoa powder, sugar, milk, and vanilla extract. Mix until smooth. Each cake should be cut horizontally.
Spread 2-3 tablespoons buttercream frosting evenly over each cake layer. Cover with buttercream frosting, and then continue the process with buttercream frosting. Use a spatula to spread buttercream frosting evenly all over the cake. Enjoy!