Preheat your oven to 350°F (175°C).
In a large bowl, whisk together the all-purpose flour, baking soda, cream of tartar, and salt.
In another large mixing bowl, use an electric mixer to cream the unsalted butter, granulated sugar, and powdered sugar together until light and fluffy.
Add the vegetable or canola oil and vanilla extract to the butter mixture. Mix until combined.
Gradually add the dry ingredients to the wet ingredients. Mix on low speed until just combined.
Cover the dough with plastic wrap and chill it in the refrigerator for at least 30 minutes.
Once chilled, scoop tablespoon-sized amounts of dough and roll them into balls. Roll each ball in additional granulated sugar before placing them on a prepared baking sheet.
Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a cooling rack.
