Grand Cru site or appellation in the Côte de Nuits region of Burgundy, which extends over two communes. The much larger part, with 13.5 hectares of vines, is located in Chambolle-Musigny and a small part with 1.5 hectares in Morey-Saint-Denis. There are several versions of the origin of the name. It is possibly derived from "bonnes mères" (good mothers or women) and refers to the order of St Bernardine nuns who owned vineyards here until the French Revolution (1789). The site was classified as a Grand Cru in 1936.

The vineyard, which faces east-south-east at around 300 metres above sea level, covers 15 hectares of vines on partly clay-limestone and marly soil with a high lime content. The Grand Cru site Clos de Tart adjoins to the north. The vineyard is divided into over 100 plots, which are shared by 35 owners.

The extremely long-lasting red wine is made almost exclusively from Pinot Noir. However, Pinot Beurot (Pinot Gris) and Pinot Liébault are also authorised, and theoretically up to 15% Chardonnay and Pinot Blanc could also be used. Well-known producers include Domaine Comte Georges de Vogüé, Joseph Drouhin, Dujac, Fougeray de Beauclair, Groffier, Jadot, Mugnier, Domaine Georges Roumier, Domaine des Varoilles and Vougeraie.