1Heat oven to 350°F (325°F for dark or nonstick pan).
2Make, bake and cool cake as directed on box for 13x9-inch pan.
3Poke cake every 1/2 inch with handle of wooden spoon. In medium bowl, beat pudding mix and milk with whisk about 2 minutes. Pour pudding evenly over cake. Run knife around sides of pan to loosen cake. Refrigerate about 2 hours or until chilled. Store loosely covered in refrigerator.