Do not prepare this frosting ahead as it will harden very quickly.
Bring first 3 ingredients to a boil in a 2-quart saucepan over medium heat, stirring often, and boil 1 minute. Remove from heat, and whisk in 1 cup powdered sugar and vanilla extract until smooth. Stir in toasted pecans, stirring gently 3 to 5 minutes or until mixture begins to cool and thicken slightly. Pour immediately over cake.
This is not only easy to make, it makes your cakes look extra special to have this on top