At the Mamiche bakeries in the 9th and 10th arrondissements of Paris, their famous pains au chocolat and croissants depend on an essential but increasingly scarce ingredient — butter.

Variables that affect butter. In the U.S., butter contains between 80% to 82% fat. European butters typically have higher fat content, which yields denser baked goods.

The amount of butter in cold storage is the lowest in five years, and about 22% lower than last year. Here's what's causing it and how to help have enough butter for the holidays.

The calmest, most practical approach is to cut hard butter into small cubes (about ½" or the size of an almond) and set it out in a single layer on a plate or the butter wrapper.