Peanut Butter Jammies

1.Lightly spoon flour into a dry measuring cup, level with a knife. Place peanut butter, sugar, and egg in a medium bowl; beat with a mixer at medium speed until smooth. Add flour, stir well. Shape dough into 36 (1-inch) balls; place 1-inch apart on baking sheets coated with cooking spray. Press thumb into center of each cookie; leaving an indentation. Cover and chill 3 hours.
2.Preheat oven to 375 degrees.
3.Bake cookies at 375 degrees for 12 minutes or until golden. Remove from pans; cool on wire racks. Spoon 1/2 teaspoon jam into the center of each cookie.