Preheat the oven to 350 degrees F. Trace the bottom of a 9-inch spring-form pan on parchment paper, and cut out a circle to lay in the bottom of the pan.
Using a food processor or high-powered blender, pulse the gingersnaps until they reach a fine crumb. Add the melted butter and egg and pulse a few more times to combine.
Press the gingersnap mixture evenly over the bottom of the spring-form pan, and up the sides approximately 2 inches. Bake for 10-12 minutes.
Once out of the oven, cut a parchment paper strip 4 inches high, and a little over 2 feet long, to line the perimeter of the pan. Tuck the parchment paper strip carefully between the crust walls and the sides of the pan. Adjust the paper ring to fit snugly around the crust the secure with a paper clip. Press the crust back gently if it has slumped a little.
Spread the entire can of dulce de leche over the bottom of the crust. Then place the crust in the freezer for 15 minutes to chill.
Scoop the ice cream into the crust and press down using a piece of wax paper. Smooth the top with a spatula. Place back in the freezer to firm up—30-60 minutes.
Then release the sides of the spring-form pan and remove the ring and parchment paper. Shake the chocolate magic shell vigorously, then drizzle around the edges. Once the edges of the cake are covered in chocolate, drizzle the magic shell in the middle of the cake. Quickly top with candied pecans, before the magic shell hardens. Place back in the freezer until ready to serve. If you plan to wait more than 1 day to serve the cake, wrap it well with foil, followed by a layer of plastic wrap.