Preheat your oven to 350°F (175°C).

Line a 12-cup muffin tin with paper liners or lightly grease with cooking spray.

In a large mixing bowl, combine the all-purpose flour, granulated sugar, baking powder, baking soda, crushed Oreos, and salt. Stir until well mixed.

In another bowl, whisk together the milk, vegetable oil, and egg until fully combined.

Pour the wet mixture into the dry ingredients. Gently fold together until just combined, being careful not to over-mix.

Divide the batter evenly among the muffin cups, filling each about ⅔ full.

Place the muffin tin in the preheated oven and bake for 15-20 minutes, or until a toothpick inserted into the center comes out clean.

Remove the muffins from the oven and let them cool in the tin for about 5 minutes before transferring to a wire rack.