In a large bowl whisk together 2 1/2 cups of flour, 1 teaspoon of salt, and 2 teaspoons of sugar. Add the cubed butter and use your clean dry hands to toss to coat with the flour.
Using your hands, work the butter into the flour, pressing the cubes of butter between your thumb and fingers.
Continue to work the flour until the mixture is shaggy and the largest pieces of butter are no larger than a kernel of corn.
Make a well in the center and add the sour cream to it.
Use a fork to work the buttered flour and the sour cream into each other until the dough begins to clump.
Separate the dough mixture into 2 equal sized piles and work each one first into a ball, and then into a disk.
Sprinkle with flour and wrap with plastic wrap.
Refrigerate for 1 hour before rolling out.
While the dough is chilling, peel, core and slice the apples into 1/4-inch to 1/2-inch slices.
As you cut your apple slices, add them to a large bowl and sprinkle a little lemon juice or apple cider vinegar to help keep them from turning brown.
Combine sugar, flour and spices in a bowl.
Add the flour mixture to the apple slices and use your hands to distribute the flour through the apples so they are well coated.
Then sprinkle with brandy and vanilla extract and stir to coat all the apples.
Place one oven rack in the lowest position and put a large rimmed baking sheet on it (to catch any drippings from the pie.)
Position a second rack the next rung up (still in the lower third of the oven) and preheat to 375°F.
Remove one crust disk from the refrigerator. Let sit at room temperature for 5-10 minutes.
Place disk on a lightly floured, clean, flat surface. Using a rolling pin, roll out the pie dough to a 12-inch circle, about 1/8 of an inch thick.
As you roll out the dough, check to make sure it isn't sticking. If and when it starts to stick, gently lift it up and sprinkle a little more flour on the table surface or on the pie dough to keep the dough from sticking.
Gently place the rolled out dough onto a 9-inch pie plate. Press down to line the pie dish with the dough.
Arrange the apple slices in the dough-lined pie plate. Mound the apples in the center.
Roll out the second disk of dough, again to 12-inches.
Gently place the second round of pie dough over the apples. Trim excess dough with kitchen shears, leaving a 3/4 inch overhang from the edges of the pie pan.
Fold the dough under itself so that the edge of the fold comes right to the edge of the pan.
Press the top and bottom dough rounds together as you flute edges using thumb and forefinger or press with a fork.
Place egg yolk and cream in a small bowl and use a fork to stir until well combined.
Use a pastry brush to brush the egg wash over the top and fluted edges of the pie. Use a sharp knife to cut slits in the top of the pie crust for steam vents.
Place pie on oven rack centered over the baking sheet on the rack below it to catch any drippings.
Bake the pie at 375°F until crust begins to lightly brown, about 20 minutes, then reduce heat to 350°F.
Transfer the apple pie to a rack to cool for at least 1 hour. Serve slightly warm or at room temperature. Great with a side of vanilla ice cream.
About halfway through baking check to make sure the pie isn't browning too much. When it's nicely browned, tent the pie with a large piece of aluminum foil to keep the pie from browning further.