A new plasmonic biosensing device based on ultrasmooth metallic surfaces with buried plasmonic nanostructures is presented. Using template stripping, ultrathin gold films with less than 5 Å surface roughness are optically coupled to buried plasmonic gratings. Because of this arrangement, light only need illuminate the buried gratings, and sensing with opaque or highly scattering liquids is possible. Picture: N. C. Lindquist et al., pp. 687, in this issue.