What characteristic defines brioche buns used in the restaurant?

Brioche buns are characterized by their rich, tender texture, which primarily comes from their high content of eggs and butter. This ingredient combination is what sets brioche apart from other types of bread. The eggs contribute moisture, richness, and a slight sweetness to the dough, while the butter lends a soft, flaky quality and enhances the overall flavor profile.

This unique formulation results in a bun that is not only soft and fluffy but also has a delightful taste that complements various fillings. It is this combination of ingredients that makes brioche buns particularly popular in culinary applications, especially for gourmet burgers and sandwiches, providing a luxurious eating experience that is sought after in many restaurants.