Preheat the oven to 350 degrees F (175 degrees C). Line a cookie sheet with parchment paper.
Beat butter in a mixing bowl with an electric mixer until fluffy. Slowly mix in cake mix and flour until combined. Add egg and beat until mixed completely. Add white chocolate chunks and mix until well combined, about 1 minute.
Form dough into 1-inch balls and place on the prepared sheet.
Bake in the preheated for 8 to 10 minutes. Cool on the baking sheet for 1 minute before removing to a wire rack to cool completely, 25 to 30 minutes..