01 - Preheat oven to 350°F. Grease and flour two 8-inch round cake pans, lining bottoms with parchment paper for easy removal.
02 - Sift flour, sugar, cocoa powder, baking powder, baking soda, and salt into a large mixing bowl. Whisk to ensure even distribution.
03 - Add eggs, milk, vegetable oil, and vanilla to the dry mixture. Beat on medium speed with an electric mixer for 2 minutes until smooth and fully combined.
04 - Slowly pour in boiling water while mixing on low speed. The batter will become thin and glossy—this ensures a moist texture. Mix until just incorporated.
05 - Divide batter evenly between prepared pans. Bake for 30 to 35 minutes until a toothpick inserted in the center emerges clean or with just a few moist crumbs.
06 - Let cakes cool in pans for 10 minutes before inverting onto wire racks. Cool completely before frosting—at least 1 hour—to prevent melting.
07 - Beat softened butter in a large bowl until creamy and pale, about 2 minutes. Gradually sift in powdered sugar and cocoa powder, mixing on low to avoid dust clouds.
08 - Add vanilla and salt. Increase speed to medium-high and beat until smooth, 3 minutes. Add milk one tablespoon at a time until spreadable consistency is achieved.
09 - Place one cooled layer on a serving plate. Spread a generous layer of frosting over the top. Position second layer and frost the top and sides, using an offset spatula for smooth edges.