Thumbprint Cookies

1 Cup Butter                                       2 cups flour
1/2 Cup packed light brown sugar        1/2 tsp salt
2 Eggs, separated                               3/4 Cup very finely chopped nuts, I roll in walnuts (If allergic to nuts,
1 ts vanilla                                          could try cereal or coconut)
                                                         Jam or jelly (I use Rasberry Jam with seeds)

Heat oven to 350 degrees. 
Mix butter, sugar, egg yolk, and vanilla thoroughly. Sift together flour and salt; stir into the first ingredients.  Roll dough into balls (about 1 tsp per ball). 
Beat egg white slightly with a fork. Dip balls in egg white and roll in nuts. Place about 1" apart on an ungreased baking sheet; press your thumb gently in the center of each or use a round instrument to make a thumbprint-sized indent. Make it fairly deep or it will puff up while baking. Bake 10-12 min. or until set. Cool. Fill thumbprints with jam. Makes about 5 to 5 1/2 doz. I have frozen with jam in with good results. Some say to freeze without jam and add it later.