Preheat oven to 350 degrees F.
Prepare a baking sheet by either greasing it with a non-stick spray, butter, or lining it with parchment paper.
In a large bowl, using a hand or stand mixer, beat the granulated sugar, brown sugar, butter, shortening, vanilla extract, butter extract, and eggs until the batter is smooth.
Add in the flour, oats, baking soda, salt, and cream of tartar.
Mix until well combined and a soft dough has formed.
Using a medium-size cookie scoop; or a tablespoon measuring spoon, scoop out a ball of cookie dough and roll in a bowl of powdered sugar.
Move the sugar covered cookie balls to a prepared cookie sheet, bake for 12-14 minutes, or until the tops no longer look wet.
Once done, let them cool on the sheet for a minute or two before moving them to a cooling rack.