For the cake, preheat oven to 375ºF. Line base of 10-1/2 x 15-1/2-in. jelly roll pan with parchment paper; set aside.
In food processor, pulse pecans until finely ground. Set aside.
In medium bowl, sift together flour, pumpkin pie spice, baking powder and salt. In large bowl, beat egg yolks until frothy with electric mixer. Add 1/2 cup sugar; continue beating 3-5 minutes. Add pumpkin and flour mixture; mix until well combined.
In separate bowl, beat egg whites until frothy with electric mixer on medium speed. Add lemon juice; continue beating 2 minutes. Gradually add remaining 1/2 cup sugar; continue beating until soft peaks form.
Sprinkle ground pecans over egg whites; gently fold in. Fold yolk mixture into egg white mixture. Spread evenly into prepared pan.
Bake 18-22 minutes or until center springs back when touched. Gently loosen edges of cake from pan. Carefully turn cake onto cooling grid lined with a clean kitchen towel. Cool cake 3-5 minutes. Carefully remove parchment paper. Starting at a short edge, roll up cake with kitchen towel. Transfer rolled cake to cooling grid; cool completely.
For icing, in large bowl, beat cream cheese, melted chocolate and caramel topping with electric mixer on medium speed. Gently stir in whipped topping.
To fill cake, gently unroll cake. Spread about 1/3 the icing evenly over surface. Gently re-roll cake. Trim off ends of roll using serrated knife. Spatula ice outside of cake with remaining cream cheese mixture. Garnish with pecans and caramel ice cream topping, if desired.
Garnish optional: additional chopped pecans and caramel ice cream topping