Heat oven to 350°F. Lightly spray the bottom of a 9-inch springform pan with cooking spray.
In a small bowl, mix cookie crumbs and butter. Press crumbs firmly onto bottom and 1/2-3/4 inch up sides of pan. Bake 8-10 minutes or just until set. Cool completely.
Spread pecans in a single layer on a baking sheet. While crust bakes, toast for 6-8 minutes or until fragrant. Set aside to cool.
In a microwave safe bowl, warm dulce de leche with 1/4 cup heavy cream, just until pourable. Likewise, in a separate bowl, melt together hot fudge sauce with 1/4 cup cream in 20 second increments stopping to stir each time. Repeat until smooth. Both should be just warm enough to pour, not hot.
To assemble: Scoop 1/2 ice cream into cooled crust; spread evenly. Drizzle ice cream with 1/3 dulce de leche 1/3 cup hot fudge. Sprinkle with 1/3 cup pecans. Freeze 15 minutes or until ice cream is almost firm.
Repeat layers starting with remaining caramel ice cream, 1/3 warmed dulce de leche, 1/3 hot fudge and 1/3 cup pecans. Return to the freezer. Reserve 1/3 caramel, 1/3 hot fudge and 1/3 pecans for serving. (Alternatively, you may opt to use 1/2 of each on 2 layers.)
Cover with plastic wrap and freeze for at least 8 hours or overnight.
Allow to sit on counter for 5-10 minutes,then remove outer ring. Slice into desired size pieces and serve drizzled with warm reserved dulce de leche, hot fudge and pecans.
Top with a dollop of whipped topping and garnish with a piece of turtle candy, if desired.
May be made up to 1 month in advance. Store tightly wrapped in the freezer.