Preheat oven to 350 degrees. In a large bowl mix melted butter, flour, powdered sugar, and salt.
Press dough into 9x13 casserole dish. Bake for 20 minutes
In a small bowl, mix blueberries, powdered sugar & lemon juice together. Set aside
In a large bowl, mix eggs, flour, sugar, lemon juice and lemon zest.
Once crust is baked pour lemon mixture over crust.
Add blueberries all over lemon filling and bake for 25 minutes.
When cool, sprinkle with powdered sugar and cut into squares.
Makes 24 small squares