Roll 1 crust into a 12-inch circle; place in a 9-inch pie plate.
Mix sour cream, sugar, elderberries, flour, and salt together in a bowl. Spoon filling into the crust in the pie plate.
Roll second crust into a 10-inch circle; cut a few slits in the center to vent steam. Place crust over the filling. Press crusts together to seal; flute edges.
Bake in the preheated oven until top crust is golden brown, about 45 minutes. Let cool to room temperature before slicing, about 1 hour.
