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

In a bowl, whisk 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 into pans and bake for 25–28 minutes or until a toothpick comes out clean. Cool completely.

Make frosting: beat butter and cookie butter until smooth, add powdered sugar and milk until fluffy.

Assemble: spread frosting between layers, sprinkle crushed cookies, and frost the top and sides.