Line an 8x8-inch square baking pan with foil or parchment paper. Set aside.
Place the chocolate into a large microwave-safe bowl, and heat in 20 second intervals, stirring after each one, until melted and smooth.
Mix in the molasses, vanilla, and spices. The mixture will become very thick. Stir in the condensed milk.
Spread the mixture into the prepared pan, and smooth out the top. Refrigerate for 2 - 4 hours or overnight until completely set.
For the Topping
Place the chocolate into a microwave-safe bowl, and heat in 20 second intervals, stirring after each one, until melted and smooth.
Pour over the fudge, and spread out evenly. Allow the chocolate to set at room temperature or in the fridge before cutting into pieces.
Notes
Fudge can be stored in an airtight container at room temperature for 1 week, or in the fridge for 2 - 3 weeks. It also freezes well for up to 2 months. Thaw overnight in the fridge before serving.