Italian restaurants were the first to give up offering butter with bread. They replaced the butter with olive oil, which was poured into small plates and garnished with garlic or herbs. Other establishments followed suit.
Now the oil is gone and the partner for bread in many restaurants is a subtly complex little spread made with dried beans or vegetables, herbs, and sometimes a hint of heat. These hors d’oeuvres are offered in small dishes — porcelain bowls, stoneware, and, as at Mistral, beautiful mustard-colored French pottery. Whatever they’re in, the spreads are always welcome when diners sit down and want a nibble while they peruse the menu.
https://www.boston.com/ae/food/articles/2004/06/02/restaurants_cover_the_spread/