In a microwave-safe bowl add chopped dark chocolate, Condensed milk, Butter and instant coffee powder.
Microwave for 30 seconds. Rest for a couple of minutes. Then slowly whisk the chocolate till it makes a smooth mixture.
If you are still finding few lumps of chocolate, microwave again for 20 seconds. Let it rest for a minute. Then mix.
Alternatively, you can set up a double boiler. Add all the ingredients mentioned above and keep stirring until chocolate melts. The mixture should be smooth and silky.
Add chopped salted pistachio, cranberry and orange zest. Mix just until everything is well distributed. Don't overmix at this stage.
Line an 8x8 square tin with parchment paper hanging on the sides.
Pour in the mixture. Make the top smooth with a spatula. Freeze it atleaset 3-4 hours.
Once the fudge is set, take the tin out of the refrigerator. Let it rest for 20 -30 minutes. Then dip a sharp knife in hot water. Wipe the knife with a kitchen towel. Cut the fudge into neat squares.