Preheat oven to 350o. Grease and flour 2 9-inch round cake pans or a 13x9x2 line sheet cake dish. Combine flour, sugar, baking powder, and salt in large mixing bowl, and mix with electric mixer at low speed until dry ingredients are thoroughly combined. Add ¾ C milk and shortening to dry ingredients, and mix with electric mixer at low speed about 20 seconds or until dry ingredients are moistened. Beat at medium speed for 2 minutes, scraping sides of bowl as needed. Add eggs, remaining ½ C milk, and vanilla, mixing at low speed for about 20 seconds, then at high speed for 2 minutes, scraping sides of bowl as needed. Pour into prepared pan(s). Bake 9 inch round pans for 30-35 minutes, 13×9 inch sheet pan for 35-40 minutes, or until toothpick inserted in center comes out clean. Cool on racks 10-15 minutes and remove from 9 inch pans. Cool completely before frosting and frost as desired.