• Line an 8 x 8-inch pan or a 9 x 9-inch pan with foil and set aside.
• Combine the cream and sweetened condensed milk in a heavy bottomed saucepan over medium heat. Heat until it is steaming, but not boiling, stirring occasionally to keep from scorching.
• Add all of the chocolate and remove from the heat. Allow the chocolate to melt, undisturbed, for 10 minutes. After 10 minutes, whisk firmly until it is thick and shiny. You can add a few drops of flavoring extract or oil at this point, or add some powdered espresso or vanilla. Whisk vigorously again to incorporate the flavoring (if used.)
• Use a rubber or silicone spatula to spread the mixture out evenly in your prepared, foil-lined pan. Allow to cool at room temperature 12 hours or overnight so that it firms slowly.
• Take the fudge from the pan and remove the foil. Place on a cutting board.
• Using a knife heated with hot water and wiped dry, cut the fudge into 16 equal-sized cubes.
  
• Wrap tightly and store at room temperature.

Optional:

• Top each cube of fudge with a homemade marshmallow, then stick a lollipop stick (or candy cane) into the center of each block and wrap tightly. Store at room temperature.