1. Preheat oven to 350°. Bake pecans in a single layer in a shallow pan 10 to 12 minutes or until toasted and fragrant, stirring halfway through.
2. Line a 15- x 10-inch jelly-roll pan with aluminum foil; lightly grease foil. Arrange graham crackers in a single layer in prepared pan, slightly overlapping edges.
3. Combine sugar, butter, and cream in a medium-size heavy saucepan; bring to a boil over medium heat, stirring occasionally. Remove from heat, and stir in vanilla and pecans. Pour butter mixture over crackers, spreading to coat.
4. Bake at 350° for 10 to 11 minutes or until lightly browned and bubbly. Top warm bars with dark chocolate morsels. Let stand 3 minutes, and spread chocolate over bars.
5. Immediately sprinkle with salt, and slide foil from pan onto a wire rack. Cool completely (about 30 minutes). Chill 20 minutes before serving. Break into bars.