Preheat oven to 375˚F and make sure oven rack is in the middle of the oven. Spray inside bottom and sides of a 9" springform pan with cooking spray. Set aside.
In a medium bowl, whisk together flour, baking soda, and salt.
In a large bowl, whisk melted butter, brown sugar, and sugar until well combined. Add egg and vanilla and whisk until smooth.
Add flour mixture to butter mixture and use a spatula to gently stir until combined -- just until no flour is visible. Fold in chocolate chips.
Even place cookie dough in greased springform pan evenly around the bottom. Bake for 18-22 minutes or until golden brown and edges are set. Run knife along the edge of pan and unlock to remove side of pan. Let cool before icing.
For icing: Please 2 drops of orange food coloring in a container of white icing. Stir well. Place icing in a pastry bag (I used Wilton Tip #21) to pipe icing in concentric circles around cookie. Sprinkle with Halloween sprinkles. Enjoy!
Store remainder at room temperature. Cookie cake will stay fresh for 2-3 days. You can also freeze this cake for up to 2 months -- just wait to ice the cake until you're ready to eat.