Preheat your oven to 350°F (175°C).

Line a baking sheet with parchment paper.

In a mixing bowl, combine the flour, sugar, cocoa powder, baking soda, and salt.

In another bowl, beat the softened butter until creamy, then add the dry mixture gradually.

Mix in the eggs and vanilla extract until well combined.

Gradually stir in the milk until the batter is smooth and well-combined.

Gently fold in the Oreo cookie crumbs to the batter.

Using a cookie scoop, drop spoonfuls of batter onto the prepared baking sheet, spacing them about 2 inches apart.

Bake for 10-12 minutes until they are set but still soft.

Let the cakesters cool completely before adding the filling.