To prepare the chocolate layer, break chocolate bars into small pieces in a heat safe mixing bowl. Heat 1 cup heavy cream on the stove until it just beegins to boil and pour very hot cream over the chocolate bar. Whisk until the chocolate is melted and a smooth ganache remains. Sift 2 tbsp cocoa powder and 2 tbsp powdered sugar through a fine mesh strainer to sift out the clumps and fold into the ganache with a flate spatula, fold in the salt and place in the fridge to cool while you prepare the whipped cream. 

Whisk 1 cup heavy cream with ½ cup powdered sugar and a splash of vanilla extract. Whisk vigorously with a hand whisk or use an electric mixer. Mix until soft, smooth peaks form about 2 minutes. Careful not to overmix the whipped cream

Assemble the parfaits first with a layer of the cooled ganache, then the whipped cream, then either crushed oreos or berries, continue layering until the cup is filled. You should be able to make 3 servings.

Best if enjoyed immediately! You can store in the fridge for up to 4 days, but the chocolate layer will be thicker when fully chilled.