Let cool completely (sometimes I throw it in the freezer for a little bit. Make sure you set the timer for 10 minute increments because you don’t want it to even begin to freeze). To make the glaze, bring sugar, buttermilk, butter, corn syrup and baking soda to boil in large saucepan, stirring until sugar dissolves. Boil until glaze is deep amber, whisking often. Glaze will thin out and be at risk for boiling over as it caramelizes. Keep an eye on it. When it’s a deep golden color, remove from heat and add vanilla. Pour over the cake.
