How to make it

1. In large bowl, beat sugar, butter and peanut butter with electric mixer until creamy. Add egg and vanilla; beat well. In separate bowl, combine oats, whole-wheat flour, baking soda and salt; mix well. Add to creamed mixture; mix until well blended.
2. Divide dough in half. Form each half into a square-shaped log 1-1/2 inches wide and about 10 inches long. Wrap each log airtight in plastic wrap and refrigerate until firm, about 4 hours or overnight.
3. Heat oven to 350°F.
4. Lightly grease cookie sheets or spray with non-stick cooking spray.
5. Unwrap dough and slice with serrated knife into 1/4-inch thick squares. (Note: If dough crumbles when slicing, let stand at room temperature for a few minutes.) Place about 1 inch apart on cookie sheets; reshape edges with fingertips, if necessary.
6. Bake 10 to 12 minutes, until golden brown.
7. Transfer to wire racks; cool completely. Store tightly covered.
8. Up to 3 hours before serving, spread one cookie with 3/4 teaspoon jelly or preserves; top with second plain cookie to form sandwich. Repeat with remaining cookies and jelly.