Prepare the coffee reduction using this recipe. Set aside.
Add approximately an inch of water to the bottom of a double boiler and melt one cup of dark chocolate chips on medium heat. Stir every few minutes and be sure not to get any water in the chocolate. When the chocolate chips are melted, remove from heat and stir in two tablespoons of melted butter or coconut oil. Allow the mixture to cool for 10 minutes.
Preheat the oven to 325°F. In a large, deep bowl, combine the somewhat-cooled chocolate mixture, cream cheese, sugar, coffee reduction, cocoa, vanilla, and salt. Use an electric mixture to mix all the ingredients until smooth and creamy. Be sure to scrape down the sides every so often to ensure that everything is well combined. Be sure not to use the slowest setting and do not over mix.
Put the filling in the spring form pan and using a small offset spatula, smooth out the filling until it is even across the pan.
Bake for 30 minutes, making sure to not open the oven! Any rapid change in temperature or humidity can lead to cracking and caving.
Turn the oven off and let the cheesecake rest in the oven for another 30 minutes, without opening the door. When the time is up, let the cheesecake cool for approximately 30 more minutes before letting it chill and set up in the refrigerator for at least three hours and up to overnight.