1. Heat oven to 325 degrees. Line a 9 x 9 x 2-inch baking pan with foil.
2. Whisk flour, cocoa, baking soda and salt. Combine butter and chocolate in a large glass bowl. Microwave in three 30-second increments, stirring until smooth.
3. Whisk in sugar and flour mixture, then eggs and vanilla. Spread into prepared pan.
4. Bake at 325 degrees for 35 minutes or until pick inserted in center comes out clean. Cool in pan for 10 minutes; use foil to lift from pan to a wire rack. Cool completely.
5. With a serrated knife, slice in half horizontally. Line pan with plastic wrap and insert top layer, cut side up, in pan.
6. In a medium bowl, beat cream cheese and caramel sauce. Sprinkle gelatin over 2 tbsp water in a small glass bowl and let stand 5 minutes. Microwave 15 to 20 seconds until dissolved. Beat into cream cheese mixture. Whip 1 cup of the heavy cream to stiff peaks. Fold into cream cheese mixture. Spread onto brownie layer in pan and top with remaining layer, cut side down. Refrigerate 2 hours.
7. Whisk remaining 1/2 cup cream to stiff peaks. Use plastic to lift stacked brownie from pan. With serrated knife, cut into squares. Top each square with a dollop of whipped cream, some of the caramel sauce, chocolate sauce and caramel popcorn. Serve immediately.