Lightly flour a large piece of waxed paper; place a disk of dough in center. Rolling from center outward, form into a 12-inch circle. (Use paper to rotate dough, and flour rolling pin and paper as necessary to prevent sticking.) Transfer dough (still on paper) to a baking sheet; cover and refrigerate. Repeat with second disk of dough.
Preheat oven to 450 degrees with a rack set in lowest position. Remove first circle of dough from refrigerator; wrap around rolling pin (discarding paper), and carefully unroll over a 9-inch pie plate. Gently lift edges and lower dough into the pie plate so it hugs bottom and sides. Avoid stretching the dough, which will make it shrink during baking. Refrigerate.
Place lemon juice in a large bowl. Peel, core, and cut apples into 1/4-inch-thick slices; halve crosswise, and add to lemon juice (to keep them from turning brown) as you work. Add sugar, flour, cinnamon, and salt; toss to combine.
Remove dough-lined pie plate from refrigerator. Fill with apple mixture, gently packing apples and mounding slightly in center; dot with butter. Lightly brush rim of pie shell with water. Remove remaining circle of dough from refrigerator. Lay over apples; press along moistened rim to seal. Using kitchen shears, trim overhang to 1 inch.
With floured fingers, fold overhang under itself to form a thick rim; pinch between thumb and forefinger to form a uniform edge around the rim of the pie plate.
To crimp edges: With thumb and index finger of one hand, gently press dough against knuckle of other hand; continue around pie. (Deep indentations anchor dough on rim and prevent it from sliding down sides of pie plate during baking.)
With a floured paring knife, cut 5 to 6 slits in top of pie, radiating from center; place pie plate on a rimmed baking sheet. Bake 20 minutes; reduce heat to 375 degrees and bake until crust is golden and juices are bubbling, 50 to 60 minutes more. If edges brown too quickly, cover with aluminum foil. Cool completely, at least 6 hours, before serving.