Preheat oven to 350ºF. Grease and flour a 9″ round cake pan, preferably a spring form pan. In a large mixing bowl with an electric beater, blend together the cake flour, sugar, baking powder, salt, milk, shortening, eggs, and vanilla at low speed, scraping the bowl often for about 1 minute. Then, on high speed, beat for about 3 minutes, scraping the bowl occasionally. Pour the batter into the prepared cake pan. Bake for 30-35 minutes, or until a toothpick comes out clean from the center. Remove from the pan and let cool. Then, place the cake in the freezer for about one hour to harden, making it easier to slice through (freezing is optional).