Start by making the flaky pie crust. Mix flour, sugar, and salt in a large bowl. Cut butter into chunks and add to the flour mixture. Coat the butter in the flour, then begin to pinch the butter and the flour together until it begins to form pea-sized morsels (you can also use a pastry blender or a food processor). Add the sour cream and mix until a shaggy dough forms, be careful not to overwork the dough.
Place the dough onto a lightly floured surface. Shape the dough into a rectangle and cut in half. Place the two pieces on top of each other and press down into a rectangle. Repeat once more, the dough should begin to come together and appear smooth. Cover with plastic wrap. Let the dough rest in the refrigerator for at least 1 hour (up to 3 days).
Make the crumble topping by Combining sugar, cinnamon, and flour. Mix together and pour in melted butter. Mix with your hands or a fork until crumbles form. Place into the refrigerator.
Make the Salted Caramel Sauce
Add sugar to a heavy bottom skillet over medium heat. Allow the sugar to melt completely.
As soon as the sugar is melted, add the butter and reduce the heat to low. Allow the butter to melt completely, carefully whisking - the caramel may seize up a bit, but it'll come back together.
Once the butter is melted, add the heavy cream and salt and whisk until smooth - this may take about 3-6 minutes. Once smooth, remove from the heat and pour into a heat safe container.
Make the Apple Pie Filling
First thing, peel and core the apples, then slice into ½ inch thick slices. Place sliced apples in a large pot with lemon juice, brown sugar, cinnamon, ginger, clove, nutmeg, and cardamom. Toss together and let it sit for 10 minutes.
Place a pot onto the stove over medium heat. Allow apples to cook down for 10 minutes, then add apple cider, and bring to a boil. Boil for 5 minutes, then simmer on low until apples are soft and liquid begins to reduce, about 15 minutes.
In a small bowl, mix together 4 tbsps of corn starch with remaining ¼ cup of apple cider. Whisk together until smooth and pour into the apple pie filling and mix together. Continue to cook for 5 minutes, and then add salted caramel and vanilla extract. Stir together and allow it to cool. (It will thicken as it cools)
Assemble and Bake
Preheat the oven to 400 degrees F. Gently flour a work surface. Roll the pie crust into a 12 inch circle, then place the crust into a 9-inch pie dish. Tuck in the edges of crust under and pinch so that no crust is overflowing from the pie pan.
Poke holes on the bottom and sides of the crust. Add a piece of parchment paper into the center of the pan, then fill with pie weights. Blind bake the crust for 15-17 minutes, then remove the pie weights and continue to bake for 10 minutes, until the crust is golden brown.
Reduce the oven temperature to 350 degrees F.
Add the apple pie filling, then sprinkle the crumble on top. Place the pie plate on a baking sheet (this is to prevent any spillage from leaking onto the oven floor). Bake for an additional 15-25 minutes, until the tops of the streusel are golden brown.
Drizzle Remaining salted caramel sauce on top.
Notes
Choose the Right Apple: Opt for a mix of tart and sweet apples, like Granny Smith and Honeycrisp. Tart apples balance the sweetness of caramel, and the mix gives the filling complexity and depth.
Let It Cool before slicing! Let the pie cool for at least an hour before slicing. This step helps the filling set and makes it easier to serve.
No need to use an egg wash: we are prebaking the crust so there's no need to add an egg wash as it will brown on its own.