2In a pan on stove melt the chocolate with the butter. Remove from heat.
In a large bowl mix the sugar with the melted chocolate. Add the eggs and the vanilla. Stir in the flour and mix well. Pour into prepared pan and bake about 25 minutes. don't overbake. cool
3To make the frosting Mix the butter, buttermilk, and cocoa powder in small saucepan whisking until smooth.
Remove from heat and pour in large bowl. Add the vanilla. Add the powdered sugar 1 cup at a time mixing continuously until desired consistency. Should be fluffy and thick adding more or less powdered sugar as needed.