Preheat oven to 375 degrees. Grease a 9-inch cake pan. In a mixing bowl, beat together egg yolks, sugar and shortening. Sift together flour, baking powder and salt. Stir dry ingredients into egg mixture along with the unbeaten egg whites just until well mixed. Stir in milk and vanilla. Fold in raspberries. Pour into prepared pan and bake until the center springs back to the touch, about 30-40 minutes.