How to Make It
Heat oven to 375° F with the rack in the lowest position. Place the dough on a floured work surface. With a floured rolling pin, roll the dough into a 12-inch circle. Transfer to a 9-inch pie plate. Trim the dough to a 1-inch overhang and tuck under itself to form a thick rim; crimp the edge. Chill for at least 30 minutes.
Meanwhile, combine the brown sugar, 3/4 cup of the flour, the cinnamon, and 1/4 teaspoon of the salt in a small bowl. Add the butter and mix until evenly moistened. Chill for at least 30 minutes.
In a separate bowl, combine the apples, pears, raisins, granulated sugar, lemon juice, the remaining 3 tablespoons of flour, and the remaining 1/2 teaspoon of salt. Transfer the mixture to the chilled piecrust and top with the chilled crumb topping.
Bake until the juices are bubbling and the crust is golden brown, 1 hour to 1 hour, 10 minutes. Let cool.