Refrigeration is your friend, especially if your dump cake has any perishable ingredients. Think milk, eggs, butter, or yogurt. Those are basically party invitations for bacteria. You wouldn’t leave a quiche out all day, right? Same energy here.
But here’s the spicy truth: if your dump cake is a fruit-only version (like canned cherries with boxed cake mix and margarine), you can sometimes get away with leaving it out for a day. Sometimes. But I wouldn’t risk it. Not if you value your digestive system.
What about the “no-egg” dump cakes?
Oh, you thought you were clever? You made a dump cake without eggs, using just fruit and cake mix and butter? Good for you! But butter is still dairy, my friend. And dairy left at room temperature for more than two hours is a no-go. The USDA says so, and they’re basically the food police.
Also, fruit fillings (even canned ones) can ferment if left out too long. Ever had a fizzy blueberry? Don’t. Just don’t.
