Thumbprints

Preheat oven to 375 degrees F. In large bowl, with mixer at medium speed, beat margarine or butter, brown sugar, egg yolk, and vanilla until light and creamy, occasionally scraping bowl with rubber spatula. At low speed, add flour and salt, and mix just until evenly moistened. With hand, press dough together to form a ball. In small bowl, with fork, beat egg white lightly. Spread pecans on a sheet of waxed paper. Shape dough by rounded teaspoons into 1-inch balls. Dip balls in egg white, then roll in pecans, gently pressing nuts onto dough. Place balls, 1 inch apart, on ungreased large cookie sheet. Bake cookies 5 minutes. Working quickly, remove cookie sheet from oven and, with end of wooden spoon, make small indentation in center of each ball. Return to oven and bake cookies 8 minutes longer or until lightly browned. Transfer cookies to wire rack to cool completely. Repeat with remaining balls. When cookies are cool, fill each indentation with a rounded 1/4 teaspoon jam. If not serving right away, allow jam to set, then store cookies, with waxed paper between layers, in tightly covered container up to 1 week.