Preheat oven to 325F; line 28 muffin wells with paper liners and place 1 chocolate sandwich cookie in the bottom of each.
Use a handheld electric mixer to beat the cream cheese until smooth in a large bowl.
Cream in the eggs and sugar, and then the sour cream, lemon juice, and vanilla.
Crush 12 chocolate sandwich cookies and fold them into the cheesecake batter.
Divide the batter between the prepared muffin wells; bake until the cheesecakes are set along the outside, but still slightly jiggly in the center, about 20 minutes.
Immediately turn off the oven and open the oven door about 2 inches. Allow the cheesecakes to come to room temperature like this, making sure the door stays ajar (it will take a couple hours).
Once at room temperature, refrigerate the cheesecakes at least 4 hours before serving.
Serve topped with whipped cream and chopped chocolate if desired.