Set bread cubes aside in mixing bowl.
Toast hazelnuts for 5 minutes at 375.
Crisp prosciutto for 10 minutes at 375.
Continually whisking, heat heavy cream, milk, and cocoa on stove to boiling.
Turn off heat, add nutella, whisk until fully incorporated.
Beat egg yolk with sugar.
Whisk chocolate mixture into egg mixture, slowly.
Add in half of the chopped nuts.
Option: You can also add in crispy prosciutto (very fine pieces). Prosciutto can be of a different size, so you can be judge on how much to make.
Wrap in plastic for one hour.
Spoon into baking cups. Bake at 350 for 21 to 25 minutes.
Sprinkle with chopped hazelnuts and crumbled crispy prosciutto.
Serve with a dollop of whipped cream.