Like many French patisserie items, including the distinctive baguette, croissants aren't really intended to be stored for consumption the next day. For a start, the light, flaky crust and soft interior dough seem to demand instant devouring as they release alluring aromas straight from the oven. Secondly, a morning visit to the bakery is a French rituals that is practically sacrosanct. However, when the situation requires storage -- or your lifestyle is not steeped in Gallic tradition -- croissants can keep overnight.
Wrap the croissants in aluminum foil or plastic wrap to seal in moisture, and place in a plastic bag. Store at room temperature. While the croissants should be wrapped tightly, take care not to crush the delicate shell.
Put foil- or plastic-wrapped croissants inside a plastic bag and place them in the refrigerator. Chilling the croissants in the refrigerator rather than storing them in the pantry is advisable if room temperatures are particularly warm.
Restore some of the croissant’s former vitality and revive the aromas the following day by reheating them for 3 to 4 minutes in a pre-heated oven at 350 degrees Fahrenheit.
Place cold croissants on a plate and reheat for 10 to 15 seconds in the microwave on full power if time is of the essence. Compared to heating in the oven, however, the microwave approach sacrifices crispiness for speed.