Cream peanut butter, powdered sugar, and milk in small bowl.
Spread a rounded teaspoonful of mixture on 24 crackers, top each with remaining 24 crackers, pressing down firmly but gently.
Place on waxed paper lined tray.
Combine chocolate chips and shortening in 1 quart glass mixing bowl.
Microwave on high uncovered for 1 1/2 to 2 minutes or until melted.
Stir well.
Using fork, place filled crackers into chocolate one at a time.
Turn to coat.
Place back on tray.
Refrigerate until set.
Store in cool place.