Preheat oven to 350 degrees F
In a large mixing bowl, add the cake mix, flour, oil, sour cream and eggs. Mix well. Dough will be thick and stiff and possibly sticky.
Scoop tablespoon sized dough onto a parchment lined baking sheet. Use the bottom of a glass, dipped in sugar to flatten cookies to about ¼ thickness.
Bake 10 minutes. Cool on a wire rack.
When cookies are completely cool, frost.
Beat butter and cream cheese in a bowl until mixed well. Add vanilla and sugar and beat until mixed well, scraping bowl down if necessary.
Frost cookies with a generous dollop of frosting and top with a whole pecan.