Ingredients
Method
Step-by-Step
- Preheat the oven to 350°F. Grease a 10-inch round cake pan or oven-safe skillet, then line the bottom with parchment for easy removal.
- Beat the softened butter, brown sugar, and granulated sugar for 2 minutes until creamy. Add the egg and vanilla, mixing until smooth and fully combined.
- Whisk the flour, cornstarch, baking soda, and salt in a separate bowl. Add the dry ingredients to the butter mixture and mix just until no dry streaks remain.
- Fold in the chocolate chips, reserving a small handful for the top if desired. Press the dough evenly into the prepared pan, keeping the surface level.
- Bake for 22 to 26 minutes, until the edges are golden brown and the center looks set but slightly soft. Do not wait for the middle to become deeply brown, because the cookie continues cooking as it cools.
- Cool the cookie cake in the pan for 20 minutes, then transfer it to a rack and cool completely. Pipe or spread buttercream around the edge, add sprinkles if wanted, and cut into wedges.
Notes
For the softest texture, measure flour with a kitchen scale or spoon it lightly into measuring cups. Store the cooled cookie cake airtight at room temperature for up to 3 days, or freeze undecorated slices for up to 2 months.
