Preheat oven to 325°F (160°C) and place a paper liner in each cup of a 12-cup muffin tin. Place 1 whole Oreo cookie flat in the bottom of each liner.

Beat the cream cheese and sugar until smooth. Mix in the sour cream, vanilla, and salt. Add the eggs one at a time, mixing on low just until blended.

Chop the 4 extra Oreos into small chunks and fold them into the batter with a spatula.

Divide the batter evenly over the Oreo bases, filling each liner nearly to the top. Bake for 22-24 minutes until the edges are set and the centers jiggle slightly. Cool in the pan for 10 minutes with the oven door cracked, then cool on a rack and refrigerate for at least 4 hours.

Pipe whipped cream on top of each chilled cheesecake and press a mini Oreo into the cream. Serve cold.