Combine the sugar and 1 teaspoon cinnamon in a small bowl and set aside. Melt 1 tablespoon butter. Spread the melted butter over the pie crust and sprinkle evenly with the cinnamon sugar. Bake until golden brown, 8 to 10 minutes. Let cool completely, then crumble and set aside.
Melt the remaining tablespoon butter in a medium saute pan. Add the apples, vanilla, a pinch of salt and the remaining 1/2 teaspoon cinnamon. Cook, stirring occasionally, until the apples are soft, 12 to 15 minutes. Remove from the heat and allow to cool completely.
Build your sundaes starting with the ice cream, dipping the scoop in a mug of hot water if necessary. Top with the sauteed apples, pie crust crumbles, caramel sauce and candied pecans. Serve immediately.