If using chocolate bars, chop them small.
Line an 8-inch square tin with parchment paper.
In a saucepan, add condensed milk, instant coffee powder, butter, salt, and orange zest. Warm it on low heat for 2-3 minutes. Make sure it doesn't come to a boil.
Fold in chopped chocolate, cranberry, and pistachio. switch off the flame and let the mix rest for 5 minutes, allowing the chocolate to melt. ( Letting the mix undisturbed is important, else the chocolate will freeze).
Mix the chocolate again until all of it has melted and no chunk of chocolate is remaining.
Empty the chocolate mixture into the prepared tin, spread the mix evenly, and smooth the surface with a spatula.
Cover with a cling wrap and refrigerate for at least 4-5 hours.
Once the fudge is set, take the tin out of the refrigerator. Let it rest for 5-10 minutes. Then dip a sharp knife in hot water. Wipe the knife with a kitchen towel. Cut the fudge into neat squares.