Stadhouderskade 40-41 was also known as the white sugar cake and has been designated a National Monument because of its architectural value and its urban planning special position, near the Rijksmuseum. In the interior, the original structure of the front rooms has been restored. The building has been repainted in its historic colours so that the special ornaments such as the “oeuil de boeufs” windows in the roof and “caryatids” columns on the balconies are shown to their full advantage again. On the roof, the bitumen “slates” have been replaced with real slates in two different shapes as it was originally done. On the ground floor, the extension realised in 1940 was fitted with austere “window box”, and the entrance on the PC Hooftstraat side was replaced by a modern and finely detailed steel door. The lines of the bars of this and the other steel doors were inspired by the tessellation of the monumental fencing around the front garden.

In contrast to the 17th-century canal houses but also to the closed building blocks of Oud-Zuid, the buildings around the Rijksmuseum are diverse, individual and, by Amsterdam standards, large-scale in nature. The Stadhouderskade 40-41 building is an example of this. Built in 1883-1885 as a double residential villa to a design by architect Jean Servais in an eclectic style, it has both classicist and Louis XVI style elements. One of the few buildings on Stadhouderskade, it has a private front garden.
First residents of number 40 were the family of Gubert Dietegen baron De Salis. De Salis (1851-1890), a merchant by profession, was a lover of sports and active as a board member of various sports associations. He arranged for the museum square to be used for horse racing, cycling, and skating from 1885. At number 41, a branch of Jewish home furnisher Hornman and Son opened in 1933. A post office sat there from 1940 until the early 1990s. An extension was built for the benefit of this post office. In 1974, the 2nd and 3rd floors of 40 and 41 were merged; the floors were used as flats until 2000, after which they were used as offices. For the past 20 years, Wanrooij Gallery and the art shop/gallery Douwes Fine Art was housed on Stadhouderskade.
Although the building has lost some features, much of the original architecture is still present and visible.