Place the Oreos (leave the filling in!) in a blender or food processor until crushed into fine crumbs. Mix the crumbs with melted butter.
Place 24 muffin cup liners in regular muffin tins. Place about a tablespoon of the crumb mixture into each muffin cup and press the crumbs down, covering the entire bottom. If you have extra crumb mixture, add more to each cup until it is all used up.
Soften the cream cheese and beat for 1-2 minutes with an electric mixer. Add 1/2 cup of the milk and mix until smooth. Add the remaining milk and pudding mixes and beat for another minute.
Fold in the Cool Whip until smooth and well combined. Spoon the filling into each muffin cup, filling just barely over the top. I like to use a muffin scoop - it's just the right size and makes it so easy to scoop the filling evenly!
Refrigerate 3-4 hours or until set. Add a little bit of whipped cream, lemon zest, cookie crumbs, lemon slices....anything you'd like for the top! Refrigerate until ready to serve. Any leftovers can be stored in the fridge for 3-5 days.