The M&M's tend to crack as they bake, and the red and green chocolate chips can turn a bit brown, so that's why I like to add some at the last minute. The fresh candies look really pretty on top. Be sure to press them down using a spatula or spoon.
You can also place a cookie sheet on the baking rack above your pan of Christmas Magic Bars while in the oven. The cookie sheet will shield the bars from getting too brown on top.
Allow the Christmas Magic Bars to cool completely before cutting.
The edges will get a bit crunchier than the inside bars.
Christmas Magic Bars https://hungryhappenings.com/christmas-magic-bars-recipe-oreo-layer-bar/