These treats remind me of a cookie recipe my grandmother used to make called Butterfingers, except hers were dipped in powdered sugar. They would just melt in your mouth. This is a similar kind of butter and nut cookie.
Heat oven to 325°F. Fold 1 sheet of foil in half lengthwise. Fold the double-thickness foil crosswise into 1-inch pleats to make an "accordion-pleated" pan. Place on ungreased cookie sheet. Repeat with second sheet of foil.
In large bowl, combine margarine and sugar; beat until light and fluffy. Add vanilla and eggs; beat well. Lightly spoon flour into measuring cup; level off. Add flour and salt; mix well. Stir in walnuts. Drop rounded teaspoon of dough into each fold of foil. (Dough spreads during baking to form 4 ½ to 5-inch long cookies.)
Bake at 325°F. for 18-26 minutes or until golden brown. Remove cookies from foil; cool completely. Turn foil over for second baking.