Preheat oven to 350. Bake pecans in a single layer in a 15 x 10 inch jelly roll pan 5 to 6 minutes or until toasted and fragrant, stirring halfway through. Cool completely.

Melt caramel bits and cream in a heavy saucepan over medium heat, stirring until smooth. Remove from heat; stir in vanilla.

Using 1 Tbsp. caramel mixture at a time, spoon circles close together over pecans, covering entire pan. Chill 10 minutes or until caramel is firm. Carefully lift candies, and transfer to a serving platter, reserving remaining pecans in pan. Redistribute pecans on pan into solid single layer. Repeat procedure with remaining caramel mixture, spooning circles over remaining pecans.

Meanwhile, microwave bittersweet chocolate and 2 tbsp shortening in a small microwave safe bowl at HIGH 30 seconds or until melted. Stir until smooth. Repeat procedure with white chocolate and remaining 2 tbsp shortening. Stir until smooth. Spoon 1 tbsp chocolate (either bittersweet or white) onto each caramel turtle candy. Sprinkle lightly with salt, if desired. Let candies harden at room temperature or in refrigerator.