Pour the heavy cream, sweetened condensed milk, vanilla, and cocoa powder to your bowl and mix with your hand mixer, or stand mixer, until firm peaks form, about 3-5 minutes.
Add in half of the chopped chocolate bar and gently stir. Save the rest of the chopped chocolate for serving.
Pour the mixture into your loaf pan and smooth out.
Set in the freezer and allow to freeze for a minimum of 4 hours.
Allow to thaw slightly before serving and topping with more chopped chocolate or chocolate sprinkles.