I'm not usually a fan of using box cake mixes; at least not for their intended purpose. Here is a recipe for Red Velvet Crinkle cookies that start with a box of Red Velvet Cake mix.
1 Box Red Velvet Cake Mix
6 T unsalted butter, melted
1 tsp vanilla extract
1/2 cup powdered sugar
1/2 tsp corn starch
Preheat oven to 375 degrees. Cover two baking sheets with parchment paper, set aside.
In the bowl of a stand mixer, beat together the melted butter, cake mix, eggs & vanilla until fluffy & smooth.
In a shallow bowl, sift together 1/2 cup powdered sugar & 1/2 tsp. corn starch. Roll cookie dough into 1 inch balls and then roll in the powdered sugar mixture. (If you run out of powdered sugar, sift together an additional 1/2 cup powdered sugar & 1/2 tsp. corn starch).
Place cookie dough balls on the prepared baking sheets, space them about 2 to 3 inches apart as the cookies spread out quite a bit.
Bake for 9 minutes exactly. The cookies will not look done, but they will set up more as they cool. Remove from oven and allow to cool on the cookie sheets for 1 minute and then place cookies on a cookie sheet to cool completely. Store in an airtight container.
6 days ago