Preheat the oven to 350 F. Line a 12 cup muffin pan with paper liners. In a large bowl, mix together cake mix with eggs, vegetable oil, and peanut butter until smooth.
In a shallow dish, combine granulated sugar and ground cinnamon. Roll the cookie dough into balls, and roll each one into the cinnamon sugar mixture. Place the cookies into the prepared paper liners. Bake for 12-15 minutes.