Double-Crust Apple Pie

Make the pastry. Whisk the 60 g sour cream with the 90 ml ice-cold water. Mix the flour, sugar and salt, then rub or pulse in the butter until the pieces are no bigger than peas, add the sour-cream water and mix until the dough clumps with no dry flour left. Knead briefly, halve, press into 2 discs, wrap and chill 1 h; the acidity of the sour cream keeps the crust tender.

Precook the apples. Peel, core and cut the apples into 5 mm slices, then toss with the caster sugar, brown sugar, salt and spices in the pot. Cover and cook over medium heat 10-15 min, stirring gently every few minutes, until the slices just bend without breaking. Stir in the cornflour mixed with the lemon juice and simmer 1 min until glossy; off the heat add the zest and vanilla, spread on the tray and cool completely, about 30 min. Cooking first shrinks the apples now rather than in the oven, so no hollow forms under the top crust.

Roll the rounds. Roll 1 disc to a 30 cm round, ease it into the dish and leave the overhang. Roll the second disc to a 28 cm round for the lid. Keep both cool while you work so the butter stays in flakes.

Fill and seal. Heat the oven to 220 °C (200 °C fan) with a baking tray on the lowest shelf. Pile the cooled apples into the lined dish, leaving most of the syrup behind, lay the top round over, trim both layers to a 1 cm overhang, fold under and crimp. Cut 4 short vents, brush with egg, sprinkle with the 1 tbsp sugar and chill 15 min. Cool filling and chilled pastry mean the crust starts baking before the butter can melt out.

Bake hot, then lower. Set the pie on the hot tray and bake 20 min, then lower to 190 °C (170 °C fan) and bake 35-45 min more until the crust is deep golden and thick juices bubble through the vents. Cover the edge with foil if it browns too fast. The hot tray crisps the base, and bubbling juices show the cornflour has fully thickened.

Cool before slicing. Cool on the rack at least 3 h so the filling sets, then slice into 8. Keep at room temperature, loosely covered, for 1 day, or chill up to 4 days and warm slices at 180 °C (160 °C fan) 10 min. Cutting too soon lets the still-liquid juices run out.