Melt the chocolate chips in a microwave. Start with 1 minute at 50%, stir and then microwave for about 15 seconds at 50% power. Stir and microwave for another 15 seconds, if required, or until chocolate is nice and smooth.
In a large mixing bowl with whisk attachment, beat cream cheese until fluffy.
Add sweetened condensed milk and beat until smooth.
Add eggs, one at a time, beating well after each one.
Then add sour cream and give another good stir.
Now, stir in flour, espresso powder, vanilla extract and salt.
And finally, add melted chocolate and mix the batter until smooth, 1-2 minutes.