Directions
Lightly grease the inside of your slow cooker with cooking spray or a thin layer of butter, or line it with a sheet of parchment paper for the easiest possible cleanup and removal. A 5- to 6-quart slow cooker works best for this recipe and gives the dough enough room to spread as it cooks.
Remove the frozen cookie dough log directly from the freezer and place it right in the center of the prepared slow cooker. Do not attempt to thaw it first and do not cut it up or break it apart at this stage. The intact frozen log will melt and spread slowly and evenly as the heat builds, which is exactly what creates that beautifully thick, even texture throughout the finished dish.
Pour the sweetened condensed milk evenly over and around the frozen cookie dough log, making sure it coats the top and flows down the sides. Then pour the whole milk or evaporated milk over the top as well. These two liquids are what transform the cookie dough from a dense baked cookie into something closer to a warm, gooey, richly flavored cookie pudding as everything melds together during cooking.
Scatter the chocolate chips evenly over the top of the dough and liquid, distributing them as generously and evenly as you can. They will melt partially into pools as the dessert cooks and remain partially intact in others, creating that irresistible variation of textures in every spoonful.
Place the lid securely on the slow cooker and set the heat to LOW. Cook for 2.5 to 3 hours, until the cookie dough is fully cooked through, the center is set but still soft and gooey rather than firm or dry, and the edges are pulling away slightly from the sides of the insert. Resist the urge to lift the lid during the first two hours of cooking — every time you peek, you release heat and add significant time to the cooking process.
