An underground restaurant, sometimes known as a supper club or closed door restaurant, is a social dining restaurant operated out of someone's home, generally bypassing local zoning and health-code regulations. They are usually advertised by word of mouth or unwanted advertising.

"Secret dining," often referred to as underground dining or supper clubs, involves culinary experiences held in non-traditional, often undisclosed locations such as private homes, converted lofts, or even hidden backrooms of existing businesses. In 2026, this trend has evolved into a high-end niche where "in-the-know" foodies join exclusive mailing lists or apps to receive a text message with a location and a password just hours before the meal. These dinners usually feature a set "tasting menu" prepared by a chef who may be testing new concepts outside of their professional restaurant kitchen. The appeal lies in the exclusivity, the intimacy, and the social aspect, as diners often sit at a communal table with strangers. Secret dining can also refer to "blind" menus where guests don't know what they are eating until it is served. This movement is a pushback against the standardized commercial dining experience, offering a sense of "urban adventure" and a chance to experience gourmet food in a raw, unpretentious, and highly personalized environment that focuses purely on the artistry of the food and the conversation.