Apple Pie

Method

1. mix15 min
   everything refrigerator-cold
   flour + salt + 1 tbsp sugar, then cut in the cold butter until the largest pieces are the size of peas and the rest is coarse meal + ice water a tablespoon at a time only until the mass holds when squeezed. The pea-sized butter is the whole point: it stays solid until the oven, then flashes to steam and pries the dough into layers. Butter warmed to the texture of paste blends into the flour instead and bakes mealy, and every extra spoon of water builds gluten you will taste as toughness. Divide in two discs, one slightly larger.
2. rest60 min
   wrapped, refrigerated
   the discs, so the flour finishes absorbing the water and the gluten you did develop relaxes. Roll a dough that has not rested and it will spring back in the tin, then shrink down the sides in the heat and drop the top crust onto the filling.
3. marinate30 min
   room temperature, in a colander over a bowl
   sliced apple + sugar + brown sugar + salt pinch + lemon juice, tossed. Sugar draws a surprising half cup of liquid out of the fruit by osmosis. Drained off now, that water cannot boil into steam under a sealed lid and collapse the apples into a shrunken puddle.
4. reduce10 min
   medium, to a thin syrup
   the drained apple liquid + 2 tbsp butter, until it thickens and darkens slightly, then pour it back over the apples with the cornstarch + cinnamon + nutmeg. You have concentrated the apple flavour rather than thrown it away, and the fruit now carries far less free water for the starch to hold.
5. fold15 min
   oven preheating to 425°F with a rack low
   roll the larger disc and line a 9-inch tin, mound the filling level with the rim, drape the second crust, trim, then fold the top edge under the bottom and crimp so the seam is sealed against leaking. Cut four vents. Brush with egg beaten with milk and scatter coarse sugar — the wash browns, the vents let steam escape instead of ballooning the crust.
6. bake25 min
   425°F, low rack
   the assembled pie, hot and low, to set and brown the bottom crust before the filling juices reach it. This is the only window you get: once the interior is wet and simmering, the base can no longer crisp.
7. bake40 min
   375°F, until juices bubble thickly at the vents
   lower the heat and finish. The visible cue is bubbling that is slow and glossy rather than watery — that is the cornstarch gelatinising, and it happens only above roughly 200°F throughout. Pull the pie while the bubbles are still thin and the slice will run no matter how long it cools.
8. rest180 min
   on a rack, uncovered, to barely warm
   the pie, at least three hours. The starch gel and the apples' own pectin only firm as they cool; cutting at an hour gives you sauce and a hollow shell. Uncovered matters too — a cloth or foil traps steam against the crust and softens it.