Bring to boil the water, cocoa and oleo.
Combine the flour, sugar, baking soda and salt.
Pour cocoa and butter mixture over dry ingredients. Mix well.
Add buttermilk, eggs and vanilla. Mix well and pour in large sheet pan (Cookie sheet pan).
Bake at 375° for 20 to 25 minutes.
Use icing recipe which follows, and top the cake while hot.