Preheat oven to 350 degrees F.
Gently roll your pie dough to fit a 9-inch pie dish. Press or crimp the edge of the crust.
In a large mixing bowl, combine the blueberries, flour, sugar, lemon juice, and salt. Gently stir. Make sure the berries begin to break down and the sugar has melted with the lemon juice to create a slurry-like mixture with the blueberries. Pour the blueberry mixture into the pie crust.
To make the crumble, combine the butter, flour, sugar, and baking powder. Use a fork to mix until it begins to clump up into pea-size crumbles. Pour the crumble evenly over the blueberry mixture in the pie.
Place the pie on a baking sheet (to catch any juicy bubble-over) and bake for 45-60 minutes or until the blueberries are bubbling through the crumble topping. Remove from the oven and let cool before cutting.