Preheat oven to 350°F. Line cookie sheets with parchment or silicone mats.

In a large mixing bowl, beat cake mix, eggs and oil until well combined. Dough will be stiff.

Roll into 1-inch balls and place 2 inches apart on prepared pans. Flatten balls slightly. Bake for 8-10 minutes, or until set around edges.

Cookies will be very puffy, but flatten as they cool. Remove to wire rack to cool completely before frosting.

For the frosting, beat cream cheese and butter until smooth. Mix in vanilla. Slowly incorporate powdered sugar, then whip until light and fluffy.

Pipe or spread onto the bottom side of half the cookies. Top with remaining cookies to form sandwiches.