Éclairs

Éclairs need to cool completely on a wire rack (not a hot baking sheet) to allow steam to escape; otherwise they collapse and become soggy. Additionally, pierce the bottom of each éclair after baking and return to the oven for 5 minutes to dry the interior. If you're baking on a humid day, this step is especially important.

Yes, bake and cool the shells 1 day ahead and store in an airtight container at room temperature. Fill and glaze just before serving (within 4 hours) to maintain crispness. The unfilled shells can also be frozen for up to 1 month.

Choux pastry puffs because of steam created by the liquid in the dough and the eggs. If your éclairs didn't rise, your eggs were likely too cold (always use room-temperature eggs), your oven wasn't hot enough (verify at 400°F), or you opened the oven door during the first 25 minutes of baking. Never open the door until they're visibly puffed and golden.

Yes, chocolate pastry cream, coffee pastry cream, or even whipped cream work well, but vanilla pastry cream is the classic and canonical choice. If using whipped cream, fill just before serving, as éclairs will become soggy.

Choux dough should be thick enough to hold a peak when piped but still pipe smoothly. If too thick, your éclairs won't puff; if too thin, they'll spread too much. Each egg varies slightly; if your dough seems too stiff after adding all eggs, beat in 1 teaspoon of water at a time until you reach the right consistency.

Store filled éclairs in the refrigerator in an airtight container for up to 2 days. Do not freeze filled éclairs, as the glaze will crack. Eat chilled directly from the refrigerator; the cold pastry cream will help the shell stay crisp. Unfilled baked shells can be frozen and reheated in a 350°F oven for 5 minutes to restore crispness before filling.