Polish Tea Cakes
["1/2 c. (1 stick) unsalted butter", "1/2 c. sugar", "1 egg, separated", "1/2 tsp. vanilla", "1 c. sifted all-purpose flour", "1/4 tsp. salt", "1 c. ground walnuts or pecans", "1/2 c. sieved raspberry or strawberry preserves"]
["Beat butter and sugar in small bowl with electric mixer until fluffy.", "Beat in egg yolk and vanilla.", "Stir in flour and salt until well blended.", "Shape dough into 1-inch balls.", "Dip each ball into unbeaten egg whites, then roll in the ground nuts.", "Place on ungreased cookie sheets 2-inches apart.", "With thumb, make deep indentation in center of each ball.", "Bake in preheated slow oven (325\u00b0) for 5 minutes.", "Make fresh imprints in center of each cookie using a thimble or handle of wooden spoon.", "Bake 8 to 13 minutes longer or until pale, tan and firm to the touch.", "Transfer cookies to wire rack to cool.", "Spoon a little preserves into depression in center of each cookie.", "Makes about three (3) dozen cookies."]
["butter", "sugar", "egg", "vanilla", "flour", "salt", "ground walnuts", "raspberry"]