1. Following package directions prepare and bake brownies in foil lined pan with foil extending beyond pan edges. Cool completely in pan.
2. Remove wrappers from caramels. Using foil as handles lift brownie out of pan. Cut off brownie edges. With hands knead and roll remaining brownie until it forms one large ball. Divide brownie ball into 36 equal balls.
3. Line cookie sheet or tray with wax paper. Flatten each ball slightly; press around one caramel, covering completely. Return to tray. Refrigerate while preparing next step.
4. Line second cookie sheet or tray with wax paper. Place chocolate chips, white chips and shortening in medium microwave-safe bowl. Microwave at MEDIUM (50%) 1 minute; stir. If necessary, microwave at MEDIUM an additional 15 seconds at a time, stirring after each heating, just until chips are melted and mixture is smooth when stirred.
5. Working with 7 to 8 truffles at a time, place one truffle on fork and immediately dip into melted chocolate mixture; allow excess chocolate to drip off truffle. If necessary, scrape off excess chocolate with knife or small spatula. Place on prepared tray. Before chocolate sets garnish with sprinkles, nonpareils or chopped nuts, if desired. Coat* and decorate remaining truffles. (If chocolate mixture cools and coating becomes difficult, microwave at MEDIUM 10 to 15 seconds; stir.) Allow chocolate to set at room temperature; transfer truffles to small paper baking cups, if desired. Store in a cool, dry place. 36 truffles.
* Excess chocolate mixture can be saved to use later to decorate cookies or bars.