Thumbprint Cookies - cooking recipe

Ingredients

1/2 cup butter, softened
1/4 cup brown sugar
1 egg, separated
1/2 teaspoon vanilla
1 cup flour
1/4 teaspoon salt
3/4 cup almonds, finely chopped (or nut of your choice)
1 teaspoon jam per cookie

Preparation

Watch the video: https://youtu.be/vKI8adWk1bQ.
Mix butter, sugar, egg yolk and vanilla thoroughly. Add flour and salt and stir inches Roll dough into small balls. Beat egg white slightly with fork. Dip balls in egg white. Roll in nuts. Place on ungreased baking sheet.*.
Bake at 350 degrees for 10-12 minutes. Remove from oven and gently depress indents into a cookie with a small rounded implement while still hot. Place cookies on a cooling rack. Let cool. Pipe or spoon jam into cooled centers of the cookie.
*At this point, you could press your thumb into the cookie ball before baking, hence the name of the cookie. Not having had success with this method, I created a different method as shared above.