Place the white chocolate in a blender.
In a heavy bottomed saucepan, whisk together 1¾ cups cream, milk, egg yolks and sugar. Place the pan over medium heat and add the mint. Stir constantly until the mixture begins to simmer. When the custard is thick enough to coat the back of the spoon, remove from heat and remove the mint.
Pour the hot custard into the blender. Run the blender until the mixture is smooth.
Divide the mixture between 6 cups. Refrigerate the cups for 3 hours until the mixture is set.
Whip together the remaining cream and powdered sugar until soft peaks form. Top the pot de crèmes with whipped cream. Garnish with additional mint, if desired.