If using a stand mixer, add the flour, sugar, butter, and salt to the bowl and beat with the paddle attachment for a couple of minutes until the dough comes together in small chunks. If using a hand mixer, add all of the ingredients to a large bowl and beat together with the mixer on low speed until the mixture forms chunks.
Press half of the dough into the bottom of a greased 9 x 9 pan. Set aside the remaining dough.
Bake the dough for 10 minutes. Let cool for 10 minutes.
For the filling:
Whisk the eggs in a large bowl. Add sugar, sour cream and flour to the eggs. Mix well and then fold blueberries.
Pour blueberry mixture over baked crust and spread evenly.
Use your hands to squeeze together chunks of the reserved dough. Sprinkle on top of the blueberry mixture and bake for 50-60 minutes, until the top is golden and the blueberries are bubbly.
Let cool one hour before serving.
Notes
I have not tested this recipe with frozen blueberries, but it should work fine.This recipe would also work well with raspberries or blackberries.