• Step 1: In a medium bowl, dissolve the orange jello in the boiling water. Stir until completely dissolved, then add the cold water and stir to combine. Refrigerate the jello mixture for about 30 minutes, or until slightly thickened but not set.
• Step 2: In a separate bowl, beat the cream cheese with a hand mixer until smooth and creamy. Gently fold in the whipped topping until well combined.
• Step 3: Fold the thickened jello mixture and the drained mandarin oranges into the cream cheese-whipped topping mixture. Gently stir in the miniature marshmallows, if desired.
• Step 4: Transfer the salad to a serving dish and refrigerate for at least 2 hours, or until completely set.