Preheat oven to 350°F. Spray a 9x13" pan with nonstick cooking spray. Use the kind with flour, if you have it.

Whisk (or mix using a hand mixer) the cake mix, eggs, oil, and 1 1/4 cups of creamer until smooth (a couple of minutes). Pour into prepared pan and bake for 30-35 minutes, or until a toothpick comes out clean. Let the cake cool for 10 minutes.

Mix the sweetened condensed milk, chocolate milk, and remaining 1 cup of creamer in a large measuring cup. Use a toothpick to poke several holes all over the top of the slightly cooled cake, then pour the tres leches mixture all over the top. Let it cool completely before frosting and serving. The longer it soaks the better (you can make it the day before, store covered in the refrigerator).

Before serving, frost with cool whip or whipped cream and a sprinkling of crushed candy canes. Store in refrigerator for up to 3 days. (It'll last longer with Cool Whip than whipped cream.)