Combine all ingredients except vanilla in a sauce pot and then place over medium heat.
Stir constantly with a whisk until thickened, 5-10 minutes.
Remove from heat and stir in vanilla.
Pour into graham cracker crust or baked and cooled traditional crust. Cover and place in the refrigerator until thoroughly chilled.
For ganache, chocolate chips and cream in microwave bowl. Place bowl in microwave for 45 second intervals, stirring after each, until chips are melted and mixture is creamy and easy to blend.
Stir together until thoroughly blended and creamy. Allow ganache to cool for five to ten minutes before spreading on top of refrigerated pie.