Preheat the oven to 350. Grease and flour a 10" tube or Bundt pan. In a medium-size bowl, combine the flour, baking powder, salt, baking soda, and lemon rind. In a large bowl, using an electric mixer set on medium speed, cream the butter with the granulated sugar until light and fluffy. Add the eggs, 1 at a time, beating well after each addition. Add the vanilla nad the poppy seed filling and mix well. Reduce the mixer speed to low and alternately beat in the flur mixture and the buttermilk until well blended. Scrape the batter into the prepared pan. Tap the pan firmly on a flat surface 2 or 3 times to remove any air pockets. Bake for 45 to 50 minutes, or until the cake is golden and well risen and a cake tester or toothpick inserted in the center comes out clean. Remove the cake from the oven and set on a wire rack to cool for 10 minutes. Turn the cake out onto the rack and cool for 20 minutes. Dust the cake with the confectioners sugar if desired, and serve sliced. Recipe by: The Family Favorites Cookbook by Readers Digest Books Posted to MC-Recipe Digest V1 #995 by L979 on Jan 8, 1998