Preheat oven to 350°F. Line a 9-inch round cake pan with parchment paper and spray lightly with baking spray. Set aside.

Combine the flour, baking soda, cinnamon, and salt in a bowl and set aside.

Cream together the butter, brown sugar, and granulated sugar in a large bowl until light and fluffy, about 2-3 minutes.

Add eggs one at a time, mixing well after each addition. Mix in vanilla extract.

Gradually add dry ingredients into the wet mixture until just combined. Do not overmix.

Stir in oats and raisins until evenly distributed. The batter will be thick and sticky.

Press the dough evenly into the prepared cake pan, pressing additional raisins on top if desired.

Bake for 18 to 20 minutes or until edges are golden Brown. Allow to cool completely in the pan.

Once cooled, transfer to a serving plate if necessary. Prepare the maple-cinnamon buttercream for topping.

To make the buttercream, beat room temperature butter until smooth, then gradually add powdered sugar, maple extract, cinnamon, and a tablespoon of heavy cream until desired consistency is achieved.

Frost the cooled cookie cake with the prepared buttercream, piping decorative swirls if desired.