Mix butter, sugar and vanilla thoroughly. Sift flour and salt together. Add to butter muxture and blend. Chill 30-45 minutes. Heat oven to 400 degrees F. (mod.hot). Pat dough evenly into ungreased 9-inch pan. Flute edge, Prick. Bake 10-12 minutes, or until lightly browned. Cool. Just before serving, fill with ice cream and top as desired.