Preheat oven to 350 degrees.
2.Combine cake mix, pudding, water, vegetable oil, vanilla extract, and eggs in large mixing bowl.
3.With a sturdy rubber spatula mix well to combine the wet into the dry ingredients.
4.Add in chocolate chips, mix, then add in M&Ms. Mix again to incorporate but gently not to break up the candies.
5.Pour batter (it’s going to be thick) into a ( 9 x 9 square pan or a 9 x 13 rectangle pan for thinner bars. You can also use a silicone baking dish.
6.Bake bars for about 20 minutes. Check with a wooden toothpick or skewer, you should have dry or no crumbs.
7.Remove from oven, let cool in pan on a wire rack until cooled.
8.Cut these gems into squares and take a big bite and enjoy!