Make Ahead and Storage: The pudding can be refrigerated for up to 4 days. Why It Works: Pudding falls under the classification of boiled, or stirred, custard--it's cooked on the stovetop to the proper thickness, then chilled. It's important to bring the mixture to a boil to activate the starch (in this case, cornstarch). Otherwise, an enzyme naturally occurring in the eggs will begin to consume the starch, which will make the pudding thin out as it sits in the fridge. Pro Tip: Although pudding is traditionally served chilled, I've always loved it just made, when it's still warm. It makes a great (unusual) dessert for a dinner party--even as one component in a plated dessert. You can spread some warm pudding on each plate and top with a slice of pound cake and some fresh fruit. Or later the same ingredients in a large bowl, preferably glass, to make a trifle!