Preheat oven to 425ºF. Cream together shortening and sugar. Sift together flour, baking powder and salt. Add to creamed mixture alternately with water and vanilla. Stir in finely crushed corn flakes. Knead to mix. Chill dough thoroughly. Roll out on a lightly floured board to 1/8 inch thickness. Cut with a heart cutter. Place a tablespoon cranberry sauce on half of the cookies, cover with remaining cookies with the centers cut out (with a small heart cutter, if possible). Bake on a greased sheet for 10 minutes. Makes 2 dozen filled cookies.