• Heat oven to 375 degrees

For Vanilla Cake

• In a medium sauce pan, add butter and water and bring to a boil. 
• In a large bowl add flour and sugar and whisk together. Add eggs, sour cream and vanilla, baking soda and salt and stir together. Carefully pour hot butter/water into mixture. Stir with a wood spoon until smooth.
• Pour into a buttered (or cooking spray) 15x10x1 inch baking sheet. Bake for 18-20 minutes until golden brown. Remove from oven and cool for 15 minutes.

For Icing

• In a small sauce pan, add butter, cocoa, salt and milk and bring to a boil. 
• In a medium size bowl, add 3 ½ cups of powered sugar, reserving ½ cup if needed.
• Pour hot cocoa mixture over powered sugar and mix thoroughly until smooth. Add more sugar if too thin. Pour icing over cake and smooth to edges of pan. Let cake cool for another 5 minutes. Slice and serve