Preheat oven to 350°F. Grease the bottoms of two 9x1-1/2-inch round cake pans. Line pans with waxed paper; grease and lightly flour pans. Set pans aside.
Prepare each brownie mix according to package directions for fudgy brownies. Spread batter evenly in the prepared pans. Bake about 45 minutes or until a wooden toothpick inserted near the centers comes out clean. Cool completely in pans on a wire rack. Loosen edges and carefully remove layers from pans.
Meanwhile, for caramel, in a heavy medium saucepan combine butter, 1/2 cup of the whipping cream, the brown sugar, and corn syrup. Bring to boiling over medium-high heat, whisking occasionally. Reduce heat to medium. Boil gently for 3 minutes. Stir in vanilla. Transfer caramel to a bowl. Cool completely.
Meanwhile, in a small saucepan bring remaining 1/2 cup whipping cream just to boiling over medium-high heat. Remove from heat. Add chocolate (do not stir). Let stand for 5 minutes. Stir until smooth. Cool about 15 minutes or until spreading consistency.
Place one cake layer, top side up, on a plate. Top with chocolate mixture, spreading evenly. Spoon 1/2 cup of the caramel over chocolate, spreading evenly. Sprinkle with chopped pecans. Add the second cake layer, top side up. Spoon the remaining caramel over top. Sprinkle with pecan halves. Let stand for 1 hour before serving.
Using a long serrated knife, cut torte into wedges.