Caramel sauce: Heat the sugar in a heavy saucepan over low heat, stirring occasionally for about 7 minutes. It will slowly turn golden brown. Carefully whisk in the whipping cream. Add butter and vanilla extract and cook for 1 more minute. Can be stored up to 2 weeks, if covered tightly and refrigerated.
Scoop ice cream into 4 ice cream sundae bowls. Top with the crushed cookies, chocolate chips, chopped pecans and caramel sauce.