Preheat oven to 375°F and line baking sheets with parchment paper.
In a large bowl, combine flour, baking soda, and cream of tartar. Whisk to combine and set aside.
In the bowl of a stand mixer fitted with the paddle attachment, cream together butter, oil, granulated sugar, and confectioners sugar on medium-high speed until light and fluffy, scraping the sides of the bowl as necessary.
Reduce speed to medium and add the eggs, one at a time, mixing until just combined after each addition.
Add the vanilla and coffee grounds and continue mixing until combined.
Reduce speed to low and add the flour mixture in three additions, scraping the sides of the bowl as necessary.
Using a 2-tablespoon cookie scoop, scoop cookies and place them onto the prepared baking sheet, spaced about 1 inch apart. (They will not spread much)
Bake 8-10 minutes or until the edges of the cookie start to turn golden brown.