Preheat oven to 375 degrees F (190 degrees C).

In a large bowl, cream together the butter, vegetable oil, white and brown sugars and confectioners' sugar until smooth.

Beat in the eggs one at a time

Stir in the vanilla.

Sift the flour, baking soda, cream of tartar and salt into a large bowl, and stir together.

Stir flour mixture into the creamed mixture.

Fold in the pecans.

Refrigerate dough for 30 minutes.

Roll dough into 1 inch balls or use a 1 inch cookie scoop

Place the cookie balls 2 inches apart onto ungreased cookie sheets lined with parchment paper or a silicone baking mat. Gentle press the cookies down to flatten slightly. They don’t spread much when baking

Bake for 10 to 12 minutes in the preheated oven, or until the edges are golden. Remove from cookie sheets to cool on wire racks.