Mix flour, salt, sugar.
Cut in cold butter until you get pea-size crumbs.
Add ice water (1 tbsp at a time) just until it holds together.
Split into 2 disks, wrap, chill 30–60 min.
Peel (optional), core, slice apples ~¼ inch (6 mm).
Toss apples with sugar, brown sugar, flour/cornstarch, cinnamon, nutmeg, lemon, salt, vanilla.
Let sit 10 min, then drain excess liquid into a small pot.
Heat oven to 425°F / 220°C. Put a tray on the lower rack to catch drips.
Roll bottom crust, place in pie dish.
Add apples (pile high), dot with 2 tbsp butter.
Add top crust (full or lattice). Seal edges, cut vents if full top.
Brush egg wash. Optional: sprinkle 1 tbsp sugar on top.
425°F / 220°C for 15 min
Reduce to 375°F / 190°C for 35–50 min
Bake until the filling is bubbling and crust is deep golden.
Cool at least 2–3 hours before slicing. If you cut early, it turns into apple soup with ambition.