1. Preheat oven to 375 degrees. Line two baking sheets with Gefen Parchment Paper.
2. In the bowl of an electric mixer, beat butter and both sugars until light and fluffy. Add egg and vanilla and beat to combine.
3. Add flour, cream of tartar, and baking soda.
4. Place rounded tablespoons of dough two inches apart on baking sheet. Press in cereal on top. The cookies will spread a lot, so try to press cereal into as many spots as possible. The cereal can, alternatively, be mixed into the dough.