Blend sugar slowly into the oil. Add the egg, salt and butter and blend thoroughly. Blend the flour in, slowly and thoroughly.
Roll the resulting dough into 1-inch balls and place in an ungreased cookie sheet, flattening each ball slightly with the palm of your hand.
Bake in a preheated oven at 350 degrees Farenheit for 10 minutes.
Serve warm as dessert or as a treat anytime throughout the day. In the rare event that they are not devoured immediately, Polvorones will keep in a cookie jar for several days.