Preheat oven to 325 degrees. In a food processor, grind vanilla bean and sugar until vanilla is as finely chopped as it can get, about one minute. Sift this mixture twice, making sure all larger pieces have been filtered out. Set aside.
In a large bowl, cream the butter with an electric mixer, then gradually add the vanilla sugar, continuing to beat until well creamed and smooth. Add the eggs one at a time, beating well after each addition. Gradually add the flour and salt, beating constantly. Add the vanilla and lemon juice and continue beating until well blended.
Grease and flour a 10-inch tube or bundt pan. Pour in the batter and ‘’spank'’ the bottom of the pan to distribute the batter evenly. Bake until a straw inserted into the cake comes out clean, about 1 hour 15 minutes, taking care not to overcook. Turn cake out onto a rack and let cool.