Set sous vide machine at 80C/176F.
In food processor or mixer, combine cream cheese, sugar, salt, eggs and vanilla. Mix until ingredients are combined and cream cheese is softened. Scrape down sides, add in buttermilk and mix again until ingredients evenly incorporated. Fold in crushed oreo cookies and stir well.
Pour an equal amount of cheesecake filling in each canning jar, and screw on the lid of each jar (see note). Gently submerge the entire jars in the bath using rubber tongs, and set a timer for an hour and a half.
Remove from bath and let rest on counter top for 30 minutes to cool. Once cooled, transfer the cheesecake to the refrigerator for a minimum of 6 hours to set the filling. When ready to serve, garnish with the oreo crust (recipe below) and your favorite toppings. Now enjoy these heavenly treats straight from the jar!
Preheat oven to 163/325F.
In a food processor, pulse oreos until finely crushed. Slowly pour in melted butter to mixture while pulsing. Alternatively use a bag to crush the oreos then stir in the butter by hand if you don't have a food processor!
Spread mixture in an even layer on a lined cookie sheet. Bake for 15 minutes, stirring halfway through.
Remove crust mixture from oven, and set aside to cool.