Make the Caramel Sauce

1. In a small saucepan (1-2qt) over Medium heat, melt the sugar, while stirring.  This will take several minutes, over which time the sugar will slowly begin to melt around the edges, then begin to clump, then melt fully into a golden sauce. Stir frequently until sauce if fully melted and a dark amber color, to avoid it burning. Let the sauce continue to melt until it turns a dark amber color. This should take several minutes, but you should watch closely to avoid burning the sugar.
2. Once the sauce reaches a dark amber color, immediately add the butter, 1 piece at a time and stir until butter is fully melted and incorporated.
3. Slowly add the cream.  It will bubble up significantly, and possibly spatter, especially if it is cold.  Let boil about 1 minute, and watch so it doesn’t overflow the pan.
4. Add the salt and vanilla. Stir.  Let cool until you can pour it into a bowl or jar.  Set aside. Prepare the crust.

Make the Crust

1. Preheat oven to 300F. Line a 9×13 pan with parchment paper, if you desire the ability to lift the entire dessert out of the pan. Place all crust ingredients into a large bowl, or atop a flour-covered work surface.  With your hands or a large spoon, mix until a soft dough is formed.  If the dough seems too stiff, feel free to add 1-2 T milk until it is pliable.
2. Press the dough evenly over the bottom of the pan, pressing into the corners and edges. Bake 10 minutes.  Increase oven heat to 350F. Prepare the filling and topping.

Make the Filling

1. In a large bowl, place the apple slices.
2. Mix the remaining ingredients in a small bowl.  Pour over apple slices, mix until they are all evenly coated. Place apples over the crust in an even layer.
3. Drizzle or pour 1/2-3/4 cup of the prepared salted caramel sauce over the apples.  It doesn’t need to completely cover them, just to create a nice layer of caramel for every bite.

Make the Topping

1. Mix together all ingredients except butter.
2. Using a pastry cutter, 2 knives, or your fingers, cut in the butter until it is in small (pea-sized) pieces.
3. Scatter evenly over the caramel sauce.
4. Bake in 350F preheated oven for 40-50 minutes, until dark golden brown.  Cool at least 1 hour before serving.  For best results, place in refrigerator for at least 1 hour prior to slicing.
5. Best to refrigerate prior to slicing if you can wait(!)
6. Drizzle any extra caramel or add whipped cream if you like, or eat as bars.