How to Make Cake Mix Cookies Preheat your oven. 350 degrees F is the magic number. Line two cookie sheets with parchment paper. Using two cookie sheets will make the process go faster than using one because you can't drop cookies on a hot sheet (they'll spread). Mix together the ingredients. Add the box of cake mix, 2 large (whisked) eggs, 5 tablespoons unsalted butter and 1/4 cup water to your mixing bowl. Mix well with your wooden spoon or rubber spatula until the batter is smooth and combined. If you're sticking with the original cake mix flavor, that's all there is to it. Add mix-ins. Add up to 2 1/4 cups of your favorite mix-ins and gently stir/fold them into the batter with your spoon or spatula. Drop the cookies onto the baking sheet. Using your cookie scoop, a tablespoon measure or your hands, drop cookies that are about 1 tablespoon large onto the cookie sheets, spacing them about 2 inches apart. Bake the cookies, rotating and switching the positions of the baking sheets halfway through, until the cookies start to turn golden brown on top, 8 to 10 minutes Repeat with the remaining cookie dough. Storing: When the cookies are completely cool, put them in a container with a tight lid, sliding parchment paper between cookie layers. Store them at room temperature for 3 days. Or freeze for up to 2 months.