Cheese Thumbprints

1/2 c. butter or margarine
3 oz. cream cheese
1 egg, separated
1 tsp. vanilla
1 tsp. grated lemon peel
1 c. powdered sugar
1 c. flour
1 c. crushed nuts
Raspberry jam

Cream together butter, cream cheese, egg yolk, and lemon peel. Stir in powdered sugar and flour. Chill dough about one hour. Shape dough into small balls. Beat egg white until foamy. Dip balls into egg white and roll in nuts. Place on greased cookie sheet and make indentation in center of each ball. Fill indentation with jam. Bake at 350 degrees for 10 to 15 minutes, until edges brown.