Preheat the oven to 350° F (117° C).
In the bowl of a stand mixer or in a bowl using a hand electric mixer, cream together the butter and sugar for 1 minute.
Scrape the sides of the bowl, add in the eggs and vanilla. Mix until combined.
Add in the cake mix and all-purpose flour. Mix until the dough comes together and the ingredients are thoroughly incorporated.
Scoop the dough into balls and arrange on a cookie sheet. For small cookies, use 1 ½ tbsp of dough. For medium cookies, use 3 tbsp of dough. For large cookies use ⅓ cup of dough.
Bake at 350° F (117° C) until the cookies spread, puff up and no longer look glossy on top. Small cookies: 8-10 minutes. Medium cookies: 9-11 minutes. Large cookies: 13-15 minutes.
Allow to cool on the pan for 3-5 minutes before transferring to a wire cooling rack. Enjoy!
