Cover the jam centers of these cookies with a circle of wax paper before dusting them with powdered sugar. This little trick keeps the jam a vibrant red color in these family-favorite cookies.--Jennifer Cofield
Beat butter at medium speed with an electric mixer until creamy; gradually add sugar, beating well. Add egg yolk and vanilla, beating until blended. Stir in flour. (Dough will be crumbly but easily presses together.) Form dough into a ball; cover and chill 3 hours.
Let dough stand at room temperature 5 minutes. Shape into 24 (1") balls. Lightly beat egg white. Dip each ball into egg white; roll in almonds, pressing firmly. Place balls 1" apart on lightly greased baking sheets. Make an indentation with your thumb in center of each cookie. Fill with about 1/4 teaspoon raspberry jam.
Bake at 350° for 15 to 17 minutes or until lightly browned. Remove to wire racks to cool. Cut a small circle out of wax paper to fit over jam center. Place wax paper on jam, and dust with powdered sugar; remove wax paper circle. Repeat procedure with remaining cookies and powdered sugar.
Christmas with Southern Living 2002