Heat heavy cream until hot (not quite boiling, starting to simmer). Remove from heat. Pour semi-sweet chocolate chips into heated cream and let sit covered for 3-5 minutes before stirring (heat will melt chips if you give it a chance). Add vanilla, and stir until smooth (this make take a minute so be patient), allow to cool until it's barely warm then pour over chilled cheesecake. Shave white chocolate over chocolate covered cheesecakes (optional, for decoration). Refrigerate for 30 minutes or set (do not cover).
I placed one of these mini cheesecakes, skipping the toasting crust step, into my Instant Pot (on trivet) with about 1.5 cups of water. I cooked on high pressure for 12 minutes, and natural release for 15 minutes (then release remaining pressure). I then continued with remainder of directions.
While writing up this post, I also did a trial of one of these mini cheesecakes in my 6 quart Instant Pot (notes on cooking time below recipe). It turned out comparable in flavor to one of the oven ones, and took about the same amount of time. The only notable difference is the difference in texture, the pressure cooked one has more of a custard-like texture, while the oven baked one has more of firm cheesecake texture. With these spring forms being 4 inch, I would be unable to fit a full batch in my Instant Pot at this time. I will update once I do a test run through my 12 quart GoWise.
**Additional update to pressure cooker notes: full batch of the citrus flavor have been tested in the 8 quart Instant Pot DUO, and all 6 spring forms can fit in this model, using above directions and worked perfectly!