With a mixer, beat eggs and granulated sugar for about 3 minutes.
Heat 3 cups of heavy whipping cream in a small saucepan until just hot but not boiling. With the mixer on low, pour the hot cream into the egg mixture slowly until combined.
Add the mixture back into the saucepan and place over low heat for 5 minutes, stirring constantly until thickened.
Cover and refrigerate for 2 hours until chilled, stirring occasionally.
When the mixture is completely chilled, fold 4½ cups of whipped cream into the chilled mixture until just combined. Divide mixture evenly among 3 medium bowls.
In the first bowl, fold in M&M's and melted chocolate. In the second bowl, fold in vanilla and cookie dough balls. In the third bowl, fold in peanut butter and chopped Reeseās cups.
Place one layer of Oreos into each prepared pan, and pour the 3 fillings into their individual pans.
Chill for 2 hours, or until ready to layer the cakes. Stack cakes, top with crushed Oreos, Cool Whip, and serve!
Recipe by Cooking TV Recipes at https://cookingtv-channel.com/triple-mousse-layer-cake/