Preheat oven to 350°F and prepare two 8-inch cake pans with parchment paper.

In a bowl, whisk together flour, baking powder, baking soda, cinnamon, and salt.

In a mixing bowl, beat butter, cookie butter, granulated sugar, and brown sugar until creamy.

Add eggs one at a time, then stir in vanilla.

Alternate adding dry ingredients and buttermilk to the batter, mixing until just combined.

Divide the batter evenly into the prepared pans and bake for 25–28 minutes or until a toothpick comes out clean. Cool completely.

For the frosting: Beat together the butter and cookie butter until smooth, then add powdered sugar and milk, mixing until fluffy.

Assemble the cake by spreading frosting between the layers, sprinkling crushed cookies over the frosting, and frosting the top and sides.