Preheat oven to 350°F. Lightly coat 32 1 3/4-inch muffin cups with cooking spray; set aside. In a large bowl knead together the cookie dough and crushed pretzels until combined. Roll dough into 1 1/2-inch balls and place in prepared cups. Press an indentation into each and press dough up the sides of each cup (dough should not go over the top of the cups). Bake for 5 minutes.
Remove from oven and sprinkle 1/2 cup chocolate pieces and caramel bits into the middle of the dough cups. Return to oven and bake about 6 minutes more or until light brown. Cool in pan on a wire rack at least 10 minutes; remove from pan (if cups are difficult to remove, allow to cool a little longer). Cool completely.
Place remaining chocolate pieces and shortening in a medium microwave-safe bowl. Microwave on 100% power (high) for 30 seconds; stir. Continue to cook at 15 seconds intervals until melted and smooth, stirring after each. Dip the tops of each cooled cup in the melted chocolate. Place on a tray or baking sheet. Add sprinkles while still wet. Chill 15 to 20 minutes or until set.