Heat oven to 350°F. Grease bottom and sides of square pan, 8x8x2 or 9x9x2 inches, with shortening. Drain pineapple well, reserving 3 teaspoons juice for Pineapple Glaze. In medium bowl, mix 1 cup flour, the butter and 3 tablespoons powdered sugar with spoon until flour is moistened. Press in pan. Bake 10 minutes.