Q: My cream puffs always turn out well and are very good if eaten the same day. However, if I want to bake them the day beforehand and store the shells (without filling), they tend to become soft. I have even stored them in tins....what am I doing incorrectly?
A: Cream puffs can be stored in an airtight container for up to 2 days; freeze for longer storage. If your cream puffs have softened in storage they can be crisped up in the oven before filling and serving. To re-crisp; bake uncovered in a 300°F for about 5 to 8 minutes. Cool completely before filling.
Also see this previous answer to "What is the Best Way to Store Cream Puffs?" and "Can I Air Dry Cream Puffs?"