Jam Thumbprints
["2/3 c. margarine or butter", "1 1/2 c. all-purpose flour", "1/2 c. sugar", "2 egg yolks", "1 tsp. vanilla", "2 slightly beaten egg whites", "1 c. finely chopped walnuts", "1/3 to 1/2 c. strawberry, cherry or apricot jam or preserves"]
["Heat oven to 375\u00b0. In a mixing bowl, beat margarine or butter with an electric mixer on medium to high speed for 30 seconds. Add about half of the flour, the sugar, egg yolks and vanilla. Beat until thoroughly combined. Beat in remaining flour. Cover and chill about 1 hour or until easy to handle. Shape dough into 1-inch balls. Roll balls in egg whites, then in walnuts. Place 1-inch apart on a greased cookie sheet. Press centers with your thumb. Bake in a 375\u00b0 oven for 10 to 12 minutes or until edges are lightly browned. Cool cookies on a wire rack. Just before serving, fill centers with jam or preserves. Makes about 42."]
["margarine", "flour", "sugar", "egg yolks", "vanilla", "egg whites", "walnuts", "strawberry"]