Start by preparing the dough. In a food processor, pulse the flour, butter, and salt until the mixture resembles small peas, about 15 pulses. This method ensures that the butter is nicely coated with flour.
Add the ice water all at once and process until the mixture almost forms a ball. Be careful not to over-process; we want to maintain some chunks of butter for a flaky crust.
Form the dough into a rectangle, about 6x4 inches, using plastic wrap and a bench scraper. Wrap tightly and refrigerate for at least 4 hours, allowing it to chill and firm up.
Once chilled, remove the dough from the refrigerator and let it warm slightly on the counter—just enough so it’s pliable. Divide it into two pieces, making one slightly larger than the other for the bottom crust.
Roll out the larger piece into a rectangle, roughly 11x15 inches. Carefully place it into the quarter sheet pan, pressing it into the corners and letting the excess drape over the sides. Refrigerate this while you prepare the filling and top crust.
Roll out the smaller piece of dough to about 10x14 inches and lay it on a lightly floured sheet of parchment paper. Refrigerate it to keep it cold.
Now, let’s preheat the oven to 400 degrees F. If you have a baking stone or an inverted baking sheet, place it on the center rack to heat. This will help create an even baking environment.
For the filling, line a large bowl with a clean thin cotton kitchen towel or a double layer of cheesecloth. Use a box grater to grate the apples, cores included, right into the towel. Once grated, twist the towel to extract the juice. This step helps prevent a soggy bottom crust!
In a large bowl, combine the squeezed apples with brown sugar, flour, lemon juice, cinnamon, ginger, nutmeg, and salt. Mix well, using your hands if necessary to ensure everything is evenly coated.
Take the bottom crust out of the refrigerator and pile the filling in the center, spreading out the apples to fit. Scatter the cold unsalted butter pieces on top of the filling.
Trim the excess crust to about 1/2 inch over the edge of the pan, tucking it up and over the top. Use a fork to crimp the edges securely.
Chill the assembled pie in the refrigerator for about 20 minutes. This step helps to maintain the shape of the crust during baking.
Before baking, brush the surface with heavy cream and generously sprinkle with sugar. Make a couple of slashes in the top crust to allow steam to escape.
Carefully transfer the pie to the oven, placing it on the hot stone or baking sheet. Bake for 40 to 45 minutes, or until the filling is bubbling and the crust is a deep golden brown. If the crust darkens too quickly, use a piece of foil to tent the pie.
Once baked, let the pie cool for at least 10 minutes before slicing. This gorgeous Apple Slab Pie can be enjoyed warm or at room temperature, perhaps with a scoop of your favorite ice cream!
