Preheat the oven to 375 degrees F (190 degrees C). Line baking sheets with parchment paper.
In a large bowl, mix butter and eggs until light and fluffy. Stir in cake mix, quick oats, and walnuts.
Roll dough into walnut sized balls.
Place cookies onto the prepared baking sheet, and flatten slightly with the bottom of a glass that has been buttered and dipped in sugar.
Bake for 8 to 10 minutes in preheated oven, or until golden brown. Allow cookies to cool on baking sheet for 5 minutes before transferring to a wire rack to cool completely.
