• Preheat oven to 350 degrees. Lightly oil a 10-inch springform pan or a cast iron skillet (no need to oil a well-seasoned skillet, though).
• Beat butter and sugars in the bowl of a mixer until well-blended. Add egg and vanilla and mix well.
• Add dry ingredients and mix just until incorporated. Add the chips, mixing by hand if needed.
• Using the back of a spoon or a wet hand, spread the dough evenly in the pan or skillet.
• Bake 20 minutes, or until golden. Let cool on a rack.
• If using a skillet: serve right in the pan (preferably with a scoop of ice cream in the middle).
• For a springform pan: run a knife around the edge and then release the sides of the pan, removing the bottom of the pan (or not - it's up to you) and place on a serving platter or cake stand to serve. It can be made up to a day ahead using this option.

Optional Birthday Greeting Directions:

• Melt the chocolate chips in a bowl in the microwave at 30 second intervals, or in a saucepan and then transfer to a small baggie.
• Push all of the melted chocolate to the corner of the baggie and snip off a tiny portion of the corner.
• Hold the baggie while twisting the top to push the chocolate out to write the birthday greeting on the cookie. Don't worry - it doesn't have to be perfect!