Make cookie cake

1. Preheat oven to 350°F (180°C). Prepare a 9-inch cake pan with parchment paper in the bottom and baking spray on the sides. Set aside.
2. Combine the flour, cinnamon, baking soda and salt in a medium sized bowl and set aside.
3. Add the butter, brown sugar and sugar to a large mixer bowl and beat on medium speed until light in color and fluffy, 2-3 minutes. You should be able to see the change in color and texture and know it’s ready.
4. Add the egg and vanilla extract and mix until well combined.
5. Add the dry ingredients and mix until the dough is just well combined. Do not over mix. Once it’s well combined, use a rubber spatula to help it come together to form a more cohesive ball.
6. Wrap the cookie dough in plastic wrap and chill for 1-2 hours, or until firm but pliable.
7. When the cookie dough is ready, prep the cinnamon filling. Combine the brown sugar and cinnamon in a small bowl and set aside. Melt the butter in a small bowl and set aside.
8. Cut the cookie dough ball in half and work with one half at a time. Roll the cookie dough out to about 1/4 to a 1/3 inch in thickness and try to get it in more of a rectangular shape. I used a pastry cutter to trim rounded sides off. You don’t want the rectangle/square shape to be too big or the strips you’ll cut later will be too long and hard to work with.
9. Brush the rolled-out cookie dough with melted butter, then sprinkle some of the brown sugar/cinnamon over top.
10. Cut strips that are about an inch wide. Again, you don’t want these strips to be too long or they are hard to move around without them tearing. It also helps if the cookie dough is still a little firm from chilling. If it’s warmed up too much and is hard to work with, you can refrigerate it for 10 minutes or so, until it’s easier to work with again. Roll up the first strip and place it in the center of the cake pan.
11. Coil the rest of the cookie dough strips around the center, moving outward. Start each new strip at the end of the previous strip. Shorter strips are easier to work with and it’s easiest to coil it right in the pan. All pieces don’t have to line up perfectly, it’ll all come together as it bakes. The dough won’t go all the way to the edge of the pan. There will be about 1/2 an inch left, but it will spread in the pan as it bakes and fill it completely.
12. Bake for 18-22 minutes, or until the edges begin to turn golden and the center looks set.
13. Remove from oven and allow to cool completely in the cake pan, then transfer to a serving plate. If it’s fully cool, you should be able to flip it upside down onto a cooling rack, place another cooling rack on top (which is actually the bottom of the cookie) and then flip it back over so that it’s right side up.

Make buttercream and finish

1. To make the frosting, beat the butter in a large mixing bowl until smooth.
2. Slowly add 1 cup of powdered sugar. Mix until combined and smooth.
3. Mix in the vanilla extract, cinnamon and one tablespoon of heavy cream.
4. Add the rest of the powdered sugar and mix until well combined and smooth.
5. Add additional cream, as needed, to get the right consistency buttercream.
6. Pipe the frosting onto the edges of the cookie cake (I used Ateco tip 844), then store in an airtight container until ready to serve. Because of the frosting, it should be refrigerated after about 24 hours, but should be served at room temperature. Best if eaten within 4-5 days.