Preheat oven to 350 degrees Fahrenheit.
Gather your ingredients.
In a medium bowl whisk together the flour, baking powder, baking soda, cream of tartar, and salt. Set aside.
Cream the butter and sugar together until light and fluffy.
Add the egg.
Mix in the vanilla.
Add the flour in several additions, mixing until just combined.
Here is the finished cookie dough.
Roll the dough into tablespoon-sized balls and place on a parchment-lined baking sheet. Leave one inch in between the cookies for spreading.
Bake the cookies for 8-10 minutes, or until the centers are set. Let the cookies rest on the cookie sheet for 5 minutes after baking, and then transfer them to a cooling rack.