01 - Preheat the oven to 350°F. Grease and line two 9-inch round cake pans with parchment paper.
02 - In a large bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt until well combined.
03 - Add eggs, milk, oil, and vanilla to the dry mixture. Beat on medium speed until fully incorporated and smooth.
04 - Carefully mix in the boiling water. The batter will become thin—this is normal and ensures a moist cake.
05 - Divide the batter evenly between the prepared pans. Bake for 30–35 minutes, or until a toothpick inserted into the center comes out clean.
06 - Let the cakes cool in the pans for 10 minutes, then turn out onto wire racks to cool completely before frosting.
07 - Beat the softened butter in a mixing bowl until creamy. Sift in the cocoa powder and mix until fully incorporated.
08 - Gradually add powdered sugar, alternating with milk, beating until smooth and spreadable. Add more milk if the frosting is too thick.
09 - Add vanilla extract and a pinch of salt. Beat on medium-high speed until light and fluffy.
10 - Place one cooled cake layer on a serving plate. Spread an even layer of frosting on top. Stack the second cake layer.
11 - Cover the top and sides of the cake with the remaining frosting. Use an offset spatula to create swoops and swirls for the classic Matilda look.