In the bowl of a stand mixer fitted with a paddle attachment, add the sugar, orange zest, and salt. Rub them together with your fingers until it resembles wet sand and smells aromatic.
Add the cream cheese and sour cream, and beat on low speed until fully combined and smooth. It’s very important to get all of those lumps out now!
While mixing on low speed, add the eggs one at a time, allowing each to fully incorporate into the mixture before adding another.
Scrape down the sides of the bowl with a rubber spatula, then add in the melted chocolate, orange juice, vanilla, and sifted cocoa powder. Mix on low speed until fully combined. Scrape down the bowl again to ensure everything is properly combined.
Use a large cookie scoop to portion the cheesecake batter between the 12 cups in the mini cheesecake pan, filling each about ¾ full. Smooth out the tops, then tap the pan on the counter a few times to release any air bubbles. Set aside.
For the water bath, fill a 1 quart saucepan with water and bring it to a boil. Once boiling, remove from heat and very carefully pour the water into the bottom baking sheet below the cheesecakes.
Carefully transfer the cheesecakes to the oven. Bake them for 25-30 minutes or until the tops appear matte.
Turn the oven off, crack the oven door, and leave the cheesecakes for 30 minutes.
Then, remove the cheesecakes from the oven and the water bath, and allow to cool completely at room temperature.
Finally, place the pan in the fridge uncovered to chill overnight.