Chocolate mousse in glass
Why Chocolate Mousse Was Once Called Mayonnaise

In its native French, chocolate mousse was once known as "mayonnaise au chocolat" or "mayonnaise de chocolat," or in English, "chocolate mayonnaise."

No records explain why chocolate mousse went by this name, but the dessert is more similar to mayo than you might realize, as both mix eggs with other ingredients until smooth.

In short, both mousse and mayo are egg-based mixtures with rich, creamy consistencies, which may explain the playful moniker of "mayonnaise au chocolate."

It's widely believed that "mayonnaise de chocolat" was created in the late 19th century, but there are printed recipes for "mousse au chocolat” dating back to the year 1768.