Preheat the oven to 350°F. Lightly grease a full-size (10" x 3") tube pan or angel food pan; or a 10-cup bundt-style pan., In a large bowl, beat together the butter and sugar until well combined., Add the eggs one at a time, beating well and scraping the bottom and sides of the bowl after each addition., Stir in the salt, baking powder, and vanilla., Add the flour alternately with the sour cream, starting with the flour. Add the flour about 1 cup at a time, the sour cream 1/2 cup at a time. Mix at medium speed between additions, until ingredients are thoroughly combined. The finished batter will be quite stiff., Scrape the batter into the prepared pan, leveling it with your wet fingers or a spatula., Bake the cake for 60 to 75 minutes, until a cake tester, bamboo skewer, or long toothpick inserted into the center comes out clean., Remove the cake from the oven, and gently loosen its edges., After 15 minutes, carefully turn the cake out of the pan onto a rack to cool., Store the cooled cake, well wrapped, at room temperature for several days. For longer storage, wrap securely and freeze.