Layer your mason jar in the following order (bottom to top) - sugar, flour, salt, baking soda, cream of tartar and sprinkles on top.
To make - Preheat the oven to 350.
Empty everything except the sugar into a small bowl. Place the sugar and the softened stick of butter in a separate bowl or a stand mixer. (It's ok if you don't get all of the sugar or have some flour mixed in!)
Cream the butter and sugar until fluffy. Add the egg and vanilla extract and mix until smooth.
Pour the small bowl of remaining ingredients into the mixer and combine until smooth.
Drop tablespoon sized balls of dough on a lined cookie sheet. Bake for 12-15 minutes or until the edges are golden brown.
Remove, place on a cookie sheet to cool and enjoy!