Pour batter into a greased glass 9×13 baking dish ( or use parchment paper).
Bake for 35-40 minutes or until you can insert a toothpick and it comes out clean. If you are covering with foil to keep the cookies from getting too brown on top, leave for 50 minutes or more and keep checking every 5 minutes until you can insert a toothpick and it comes out clean.
Once out of the oven quickly place the Cadbury creme eggs on top and the pastel M&M’s.