Place espresso powder and 1/2 cup sugar in a bowl. Add 1 cup boiling water. Stir until dissolved and let cool.
With an electric mixer, beat cream cheese, vanilla extract and 1/3 cup sugar until smooth.
In another bowl, use electric mixer to beat heavy cream until it forms stiff peaks.
Fold whipped cream into cream cheese mixture.
Cut twinkies in half lengthwise and lightly grease a 9-inch square baking dish.
Dip 12 twinkie halves in the espresso mixture and then arrange them side by side in the baking dish.
Spread half of cream cheese mixture on top.
Grate 2 ounces of chocolate on top of the cream cheese layer.
Dip the remaining twinkie halves in the espresso mixture and arrange them over the chocolate.
Spread the remaining cream cheese mixture on top and then grate the rest of the chocolate on top.
Refrigerate for at least 4 hours and up to 2 days.