Dissolve the Jell-O:
In a large bowl, combine orange Jell-O and boiling water. Whisk until fully dissolved.

Chill the Mixture:
Add cold water and refrigerate for 15 minutes.

Add the Pudding:
Slowly whisk in the vanilla pudding mix until smooth. Chill for another 15–20 minutes, or until slightly thickened.

Fold in the Extras:
Gently fold in Cool Whip, mandarin oranges, and mini marshmallows until evenly combined.

Serve:
Chill until ready to serve. Enjoy this creamy, fruity dessert!

Prep Time: 20 minutes
Chill Time: 30–40 minutes
Servings: 6–8