1) Preheat the oven to 350°F. Lightly grease a 9 or 10-cup Bundt pan.
2) In a large bowl, beat the butter and sugars until light and fluffy.
3) Add the eggs one at a time, beating for a minute or two between additions. Scrape the sides and bottom of the bowl.
4) Add the baking powder, salt, and baking soda, then gently beat in half the flour.
5) Gently beat in the sour cream and vanilla, then add the remaining flour, mixing just until blended.
6) Scoop the batter into the prepared pan, and bake for 55 to 60 minutes, until a cake tester or toothpick inserted in the center comes out clean.
7) Remove the cake from the oven, and cool in the pan for 15 minutes before transferring to a rack to finish cooling. Cool completely before slicing.
Yield: 1 cake, 16 slices.