A crunchy, lemony topping crowns this appealing summer dessert.
To make crust: Stir together 1 cup flour, 1 tablespoon sugar and salt in a medium bowl. Melt 1 tablespoon butter in a small saucepan over low heat. Cook, swirling the pan, until the butter turns a nutty brown, about 30 seconds. Pour into a small bowl and let cool. Stir in 3 tablespoons oil. Using a fork, slowly stir the butter-oil mixture into the flour until the mixture is crumbly. Gradually stir in enough ice water so that the dough will hold together. Press the dough into a flattened disk.
Place two overlapping lengths of plastic wrap on the work surface. Set the dough in the center and cover with two more sheets of plastic wrap. With a rolling pin, roll the dough into a circle about 12 inches in diameter. Remove the top sheets and invert the dough into a 9-inch pie pan. Gently press the dough into the bottom of the pie pan. Remove the remaining wrap. Fold the edges under and crimp. Cover loosely with plastic wrap and refrigerate while you prepare the streusel topping and filling.
To make streusel topping: Preheat oven to 375 degrees F. Stir together 3/4 cup flour, 1/4 cup sugar and 1 teaspoon lemon zest in a bowl. Add 1 tablespoon butter, 1 tablespoon oil and lemon juice and work in with your fingertips until the mixture forms small crumbs; set aside.
To make filling and bake pie: Stir together 1/2 cup sugar and tapioca in a mixing bowl. Stir in 1 teaspoon lemon zest and 1 tablespoon juice. Add blueberries and stir gently to mix. Spoon the filling into the prepared crust. Cover loosely with foil and set in the middle of the oven, with a baking sheet placed on the rack below to catch any drips. Bake for 55 to 65 minutes, or until the berries are juicy and bubbling. (Frozen berries will take about 10 minutes longer.) Uncover the pie, sprinkle evenly with the reserved streusel topping and bake for 12 to 15 minutes longer, or until the streusel is golden. Cool on a wire rack for 30 minutes, then cool completely in the refrigerator, about 2 hours.
3 other carbohydrate, 2 fat