CRUMBLE TOPPING Ingredients
1 1/4 cups all-purpose flour
1 teaspoon baking powder
1/2 teaspoon ground cinnamon
1/2 cup light brown sugar, firmly packed
8 tablespoons unsalted butter, melted
BLUEBERRY/STRAWBERRY FILLING Ingredients
3 cups blueberries, rinsed, drained and picked over
3 cups strawberries, rinsed, drained and quartered.
3/4 cup sugar
4 tablespoons cornstarch
2 tablespoons water
1/4 teaspoon freshly grated nutmeg
3 tablespoons butter, cold, cut into 10 pieces
One 9-inch pie dish
Set a rack in the lowest level of the oven and preheat to 350 degrees. (You can wait to do this until you’re about half way through the process.)
For the crumble topping – combine the flour, baking powder, and cinnamon in a bowl and stir well to mix. Stir the brown sugar into the melted butter and scrape the mixture into the bowl of flour. Use a rubber spatula to fold in the butter so that all the flour is evenly moistened. Set aside while preparing the filling.
For the filling, put 1 cup of the blueberries, 1 cup of strawberries, and all of the sugar in a medium saucepan. Set the pan over low heat and stir often to bruise the berries so that they release their juices as the mixture heats up and they dissolve the sugar. Continue to cook, stirring occasionally, until the berry mixture is boiling.
While the berry mixture is coming to a boil, whisk the cornstarch and water together in a small bowl. Stir about 1/2 cup of the blueberry juices into the cornstarch mixture, then pour the cornstarch mixture into the boiling berry juices, stirring vigorously with a wooden spoon or heatproof spatula. Cook, stirring constantly, until the juices thicken and return to a boil.
Put the remaining berries in a large bowl with the nutmeg and use a large rubber spatula to fold in the thickened juices. Fold in the butter and scrape the filling into the prepared piecrust.
Use your fingertips to break the crumble mixture into 1/4 to 1/2-inch crumbs. Evenly scatter the crumbs all over the filling.
Bake the pie until the crust and crumbs are well colored and baked through and the filling is gently simmering, about 40 minutes.
Cool the pie on a rack for at least 1 hour – and serve it at room temperature.