In a large bowl, cream shortening and sugar until light and fluffy. Beat in vanilla. Combine the lour, baking powder and salt; add to the creamed mixture alternately with milk, beating well after each addition. Beat in the egg whites.
Fill paper-lined muffin cups half full. Bake at 350° for 18-22 minutes or until toothpick inserted in the center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely. Frost cooled cupcakes; decorate as desired.