Preheat oven to 350°F.

In the bowl of a stand mixer, combine butter, granulated sugar, and confectioners' sugar and mix until just combined.

Add vegetable oil, eggs, orange juice, orange zest, and orange extract; mix well.

In a bowl, sift together cream of tartar, salt, and flour.

Gradually add the flour mixture to the butter mixture, mixing until dough pulls away from sides of the bowl.

Using a cookie scoop, portion out dough onto parchment-lined baking sheet.

Roll each dough ball until smooth and round.

Press each cookie with a glass dipped in granulated sugar to flatten slightly.

Bake for 8-12 minutes or until edges are lightly golden. Cool before frosting.

For the frosting, beat butter, sour cream, orange juice, salt, and orange extract until smooth. Gradually add confectioners' sugar to reach desired consistency. Color with orange food coloring if desired. Spread on cooled cookies.