Begin by preheating your oven to 350 degrees Fahrenheit. Lightly grease (with butter) AND line with parchment paper the bottoms of TWO 8-inch cake pans or THREE 6-inch cake pans.
In a bowl, whisk together the milk and apple cider vinegar and set aside for 5-10 minutes until everything "activates".
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt until combined.
Add in the milk-ACV mixture, oil, vanilla, and mix (using a hand-mixer) until just combined and smooth.
NOTE: If the batter looks extremely thick, add extra milk, 1 tablespoon at a time until it’s somewhat pourable but not runny or thin at all.
Fold in the crushed oreo cookies. NOTE: Ensure that you remove the cream from each cookie and crush only the chocolate cookie part.
Divide the batter evenly into each of the cake pan and bake for 20-25 minutes, or until a toothpick or butter knife comes out clean when tested in the centers.
Remove cakes from the oven and let them rest in the pan for 10 minutes or so before removing the cakes and placing them onto a cooling rack to fully cool. NOTE: Let them cool for at least 1-2 hours in a cool place.