1 and ¼ cup yellow or vanilla boxed cake mix (I typically use vanilla cake mix - you just need the DRY mix)
½ teaspoon baking soda
¾ cup unsalted butter, softened to room temperature
½ cup granulated sugar
½ cup packed light brown sugar
1 egg, at room temperature
1 and ½ teaspoons vanilla extract
½ cup chocolate chips (I used a blend of white and semi-sweet chocolate chips)
½ cup M&Ms
½ cup sprinkles
In a large bowl, sift together flour, cake mix, and baking soda. Set aside.
Using a hand mixer or a stand mixer fitted with paddle attachment, cream the softened butter and both sugars together on medium speed until smooth. Add the egg and mix on high until combined, about 1 minute. Scrape down the sides and bottom of the bowl as needed. Add the vanilla and beat on high until combined. Add the flour mixture to the wet ingredients and mix on low-medium speed until just combined. Add the chocolate chips and sprinkles. Mix on low until the add-ins are evenly disbursed.
Cover tightly with plastic wrap and refrigerate dough for at least 2 hours, or up to 3-4 days. This step is mandatory. The dough is fairly sticky, so chilling the dough is required in order to avoid the cookies from spreading too much. Roll into 1 inch balls after 2 hours. Use about 1.5 tablespoons of cookie dough per cookie. Shape your cookie dough balls to be "taller" than they are wide
Once dough has been chilled and formed into balls, preheat oven to 350°F (177°C). Line two large cookie sheets with parchment paper or silicone baking mats.
Place cold dough balls onto an ungreased baking sheet. Make sure to keep dough chilled when working in batches.
Bake the cookies for 10-12 minutes until edges are slightly browned. Mine take 10 minutes exactly. The centers will still appear very soft, but the cookies will set as they cool.
Allow the cookies to cool on the baking sheet for 4 minutes and transfer to a wire rack to cool completely.
Make ahead tip: Cookies stay fresh covered at room temperature for up to 1 week. You can make the cookie dough and chill it in the refrigerator for up to 3-4 days. Allow to come to room temperature and continue with step 4. Baked cookies freeze well - up to three months. Unbaked cookie dough balls freeze well - up to three months. Bake frozen cookie dough balls for an extra minute, no need to thaw.
Recipe by How to Decorate at https://www.ballarddesigns.com/howtodecorate/2015/12/holiday-cookie-recipe-cake-batter-cookies/