Chocolate Hazelnut Thumbprints Recipe

In a large bowl, cream butter and sugar until light and fluffy. Add the egg, yolk and vanilla; mix well. Combine the flour, cocoa and salt; add a third at a time to creamed mixture, beating well after each addition. Stir in nuts. Roll dough into 1-in. balls; place 2 in. apart on ungreased baking sheets. Using the end of a wooden spoon handle, make a 1/2-in.-deep indentation in the center of each ball; fill with 1/4 teaspoon of preserves. Bake at 350° for 10-12 minutes or until set. Remove to wire racks to cool. Just a before serving, lightly dust with confectioners' sugar. Yield: about 6 dozen.