Preheat oven to 350 degrees. Prepare two 9-inch cake pans by rubbing with butter, sprinkling with flour and tapping out extra. In a large bowl combine flour, sugar, cocoa, baking soda, baking powder and salt. Mix together with a wooden spoon then set aside. In small bowl combine eggs, milk, oil and vanilla. Beat well with hand mixer. Slowly add boiling water and mix. Add wet ingredients to flour mixture and fold and stir until smooth. Pour batter into pans, dividing evenly. Bake for 30-35 minutes. Remove cake from pans and cool on racks.