Preheat the oven to 350°F and line a cookie sheet with parchment paper.
In a stand mixer, combine the cake mix, melted butter, granulated sugar, vanilla, and eggs. Mix on low until well combined.
Add the flour and mix until just combined.
Chill the cookie dough in the refrigerator for 15-20 minutes.
Use a large cookie dough scoop to grab about 1/4 cup of dough per cookie. Flatten it into a round circle, place an Oreo in the center, and encase the cookie with the dough.
Arrange the cookies on the prepared sheet, about 2 inches apart, and gently press the dough down.
Bake for 10-12 minutes or until the edges are set. Cool on a rack before decorating.