Add the half & half and white chocolate chips to a saucepan over medium-low heat, stirring well until the chocolate has completely melted.
Increase the heat to medium-high to bring to a boil. Add the cornstarch a little at the time while stirring vigorously with a whisk for 5-6 minutes until the mixture starts to thicken.
Let cool for 1-2 minutes and pour into martini glasses. Place in the refrigerator for at least 5 hours, preferably overnight.
To serve, cover the top of each with the grated chocolate, add a layer of chopped pistachio nuts, and top with a maraschino cherry.
3 cups half & half
2-1/2 cups white chocolate chips
3-1/2 tablespoons cornstarch
1 cup grated dark chocolate
1 cup chopped pistachio nuts 1 cup whipping cream
6 maraschino cherries