Prep. Lightly coat an 8x8-inch pan with baking spray; line it with parchment paper and spray it again. Set aside.
To make the fudge, set up a double boiler. Fill a medium saucepan with about 2 inches of water and bring it to a gentle simmer.
Combine the ingredients. In a mixing bowl, one that is larger than the saucepan, combine the chopped chocolate, butter, condensed milk, and coffee. Set the mixing bowl over the simmering water, making sure it does not touch the water.
Cook. Stirring frequently, cook until the chocolate is melted and completely smooth. Then, stir in the cinnamon, chili powder, and cayenne pepper.
Pour and set. Remove the chocolate fudge from the heat and pour it into the previously prepared pan. Sprinkle the top with salt and place it in the fridge for 2 to 4 hours. For best results, chill it overnight.
Serve. Cut the fudge into about 20 to 24 squares and serve.
Notes
Store the fudge squares in an airtight container and refrigerate for up to 2 weeks, or freeze for up to 1 month.