1. Preheat oven to 350°. Bake pecans in a single layer in a shallow pan 8 to 10 minutes or until toasted, stirring halfway through. Cool completely on a wire rack (about 30 minutes). Increase oven temperature to 425°.
2. Unroll piecrusts; stack on a lightly floured surface. Roll stacked piecrusts into a 12-inch circle. Fit piecrust into a 10-inch deep-dish tart pan with removable bottom; press into fluted edges. Trim off excess crust along edges. Line piecrust with aluminum foil or parchment paper, and fill with pie weights or dried beans. Place pan on a foil-lined baking sheet.
3. Bake at 425° for 12 minutes. Remove weights and foil, and bake 4 more minutes. Cool completely on baking sheet on a wire rack (about 15 minutes). Reduce oven temperature to 350°.
4. Microwave chocolate morsels and 1/4 cup cream in a microwave-safe bowl at HIGH 1 minute or until melted and smooth, stirring at 30-second intervals.
5. Beat cream cheese and 1/4 cup sugar at medium speed with an electric mixer 1 to 2 minutes or until smooth. Add 1 egg, beating at low speed just until blended. Add chocolate mixture, beating just until blended. Spoon batter into prepared crust.
6. Microwave caramels, butter, and remaining 1/4 cup cream in a large microwave-safe bowl at HIGH 1 to 2 minutes or until smooth, stirring at 30-second intervals. Whisk together 2 eggs, vanilla, salt, and remaining 3/4 cup sugar; whisk into caramel mixture until blended. Stir in pecans; spoon over chocolate mixture in prepared crust.
7. Bake at 350° for 55 minutes to 1 hour and 5 minutes or until center is almost set, shielding edges with aluminum foil after 45 minutes to prevent excessive browning. Cool completely on a wire rack (about 2 hours).