Preheat to 350°F and prep two 9-inch pans by greasing and flouring them.
Sift the dry ingredients so the cake has a fine, tender crumb.
Add eggs, milk, oil, and vanilla and beat until the batter is smooth and glossy.
Stir in boiling water gradually to create a thin, moisture-rich batter.
Bake for 30 to 35 minutes until the layers spring back and a toothpick tests clean.
Cool completely on a rack after a brief rest in the pans.
Make the frosting by beating butter, adding powdered sugar and cocoa, then finishing with vanilla, salt, and cream until fluffy.
Assemble and frost the cake, stacking the layers and covering the whole surface evenly.