Preheat oven to 350F.
For the Crust:
Using a food processor combine flour, salt, and sugar on and pulse for 30 seconds.
Cut butter into 1/2-inch cubes and add to flour mixture and pulse until mixture looks crumbly, with bits of dough the size of peas, about 1 minute.
Add 4 tablespoons ice water, 1 tablespoon at a time, mixing on low speed for 10 seconds after each addition. After final addition, dough should begin to clump together in a ball. If it doesn’t, continue mixing for about 10 seconds longer. (If it still looks too dry, add 1 more tablespoon ice water.) Gently mold dough into a disk, cover in plastic wrap, and refrigerate for at least 1 hour.
Transfer unwrapped dough to a lightly floured surface.
Roll into a 1/8-inch-thick circle large enough to cover bottom and sides of a 9-inch-diameter deep-dish pie pan; do not use a regular (shallow) pan. Transfer dough to pie pan, crimping edges with your fingers or a fork. Prick bottom with a fork.
For the Crumb:
In a food processor fitted with a metal blade, process sugar, salt, and flour for about 1 minute.
Cut butter into small pieces and add to sugar-flour mixture. Pulse 10 to 15 times until mixture is crumbly.
Add in the mini chocolate chips and nuts and pulse one time.
Remove from processor and refrigerate topping, covered, until ready to use.
For the Filling:
In a large bowl, combine the sugar, cornstarch, pectin (if using), salt, and vanilla pudding mix.
Add the apples and toss to combine.
Put 1/3 the mixture into the prepared pie pan.
Sprinkle half the Snickers pieces over the apples.
Put another 1/3 of the apples on top of that.
Sprinkle the remaining Snickers pieces over those apples.
Top with the remaining 1/3 of the apple mixture.
Sprinkle the crumb topping over the top of the filling.
Place the pie on a baking sheet, place in the oven, and bake for 30 minutes.
Tent the pie with aluminum foil and bake for an additional 30 minutes.
Remove the foil and bake for an additional 10-20 minutes or until the pie is evenly golden brown.
Remove from oven and cool on wire rack before adding the caramel sauce.
For the Vanilla Pudding Caramel Sauce:
Combine the sugar, water, and lemon juice in a heavy bottomed saucepan over medium heat. Cook, gently swirling the pan occasionally, until the sugar dissolves and starts to turn color.
Increase the heat to thigh and boil until the syrup turns a deep amber color, 4 to 5 minutes.
Watch carefully, as it can burn quickly.
Immediately remove the pan from the heat and pour in the cream, vanilla pudding mix, and salt.
Use a long-handled wooden spoon to carefully stir in the cream, as caramel has a tendency to hiss and splash as the cold cream hits it.
Place the pan over low heat and cook, stirring constantly, until the caramel thickens, 5 to 7 minutes.
The mixture should be the consistency of very thick cream. Let boiling sauce cool until it is just warm before pouring over the pie. You will not use the full amount of the caramel sauce. Save the rest to drizzle over the pie when serving it with ice cream.