Can you leave choux pastry overnight?
Yes, absolutely. Uncooked choux pastry dough can be stored in an airtight container (or pastry bag) in the fridge for up to 2 days.
Why does choux pastry deflate?
But even if they do rise, they will deflate when they cool down, due to too much moisture inside the shell, especially if you take them out of the oven too soon. The shells didn't have enough time to form a stable crust, so they collapse as they cool down.
How long will profiteroles keep?
They are best eaten within 2 days and can be kept in an air-tight container at room temperature or in the fridge.