Combine flour, sugar, baking soda and salt. Blend in shortening and 1/2 cup peanut butter until mixture resembles coarse meal. Blend in syrup and milk.
Form into a roll 2 inches thick; chill at least 30 minutes. Cut into 1/8-inch to 1/4-inch-thick slices. Arrange half the slices on ungreased baking sheets; spread each with 1/2 teaspoon peanut butter. Top with remaining slices; seal edges with a fork.
Bake at 350° for 12 minutes or until golden.